contrib: Add deterministic Guix builds.

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diff --git a/contrib/guix/README.md b/contrib/guix/README.md
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+# Bootstrappable Bitcoin Core Builds
+
+This directory contains the files necessary to perform bootstrappable Bitcoin
+Core builds.
+
+[Bootstrappability][b17e] furthers our binary security guarantees by allowing us
+to _audit and reproduce_ our toolchain instead of blindly _trusting_ binary
+downloads.
+
+We achieve bootstrappability by using Guix as a functional package manager.
+
+## Requirements
+
+Conservatively, a x86_64 machine with:
+
+- 2 or more logical cores
+- 4GB of free disk space on the partition that /gnu/store will reside in
+- 24GB of free disk space on the partition that the bitcoin repository resides in
+
+> Note: these requirements are slightly less onerous than those of Gitian builds
+
+## Setup
+
+**If you're just testing this out, you can use the
+[Dockerfile][fanquake/guix-docker] for convenience. It automatically speeds up
+your builds by [using substitutes](#speeding-up-builds-with-substitute-servers).
+Should you choose to use the Dockerfile, you can skip this section.**
+
+Otherwise, follow the [Guix installation guide][guix/bin-install].
+
+> Note: For those who like to keep their filesystems clean, Guix is designed to
+> be very standalone and _will not_ conflict with your system's package
+> manager/existing setup. It _only_ touches `/var/guix`, `/gnu`, and
+> `~/.config/guix`.
+
+After installation, you may want to consider [adding substitute
+servers](#speeding-up-builds-with-substitute-servers) to speed up your build if
+that fits your security model. (skippable if you're using the
+[Dockerfile][fanquake/guix-docker])
+
+Once Guix is installed, deploy our patched version into your current Guix
+profile. The changes there are slowly being upstreamed.
+
+```sh
+guix pull --url=https://github.com/dongcarl/guix.git \
+          --branch=2019-05-bitcoin-staging \
+          --max-jobs=4 # change accordingly
+```
+
+Make sure that you are using your current profile. (You are prompted to do this
+at the end of the `guix pull`)
+
+```bash
+export PATH="${HOME}/.config/guix/current/bin${PATH:+:}$PATH"
+```
+
+> Note: There is ongoing work to eliminate this `guix pull` step using Guix
+> [inferiors][guix/inferiors] and [channels][guix/channels].
+
+## Usage
+
+### As a Development Environment
+
+For a Bitcoin Core depends development environment, simply invoke
+
+```sh
+guix environment --manifest=contrib/guix/manifest.scm
+```
+
+And you'll land back in your shell with all the build dependencies required for
+a `depends` build injected into your environment.
+
+### As a Tool for Deterministic Builds
+
+From the top of a clean Bitcoin Core repository:
+
+```sh
+./contrib/guix/guix-build.sh
+```
+
+After the build finishes successfully (check the status code please), compare
+hashes:
+
+```sh
+find output/ -type f -print0 | sort -z | xargs -r0 sha256sum
+```
+
+#### Recognized environment variables
+
+* _**HOSTS**_
+
+  Override the space-separated list of platform triples for which to perform a
+  bootstrappable build. _(defaults to "i686-linux-gnu x86\_64-linux-gnu
+  arm-linux-gnueabihf aarch64-linux-gnu riscv64-linux-gnu")_
+
+  > Windows and OS X platform triplet support are WIP.
+
+* _**SOURCES_PATH**_
+
+  Set the depends tree download cache for sources. This is passed through to the
+  depends tree. Setting this to the same directory across multiple builds of the
+  depends tree can eliminate unnecessary redownloading of package sources.
+
+* _**MAX_JOBS**_
+
+  Override the maximum number of jobs to run simultaneously, you might want to
+  do so on a memory-limited machine. This may be passed to `make` as in `make
+  --jobs="$MAX_JOBS"` or `xargs` as in `xargs -P"$MAX_JOBS"`. _(defaults to the
+  value of `nproc` outside the container)_
+
+* _**SOURCE_DATE_EPOCH**_
+
+  Override the reference timestamp used for bit-for-bit reproducibility, the
+  variable name conforms to [standard][r12e/source-date-epoch]. _(defaults to
+  the output of `$(git log --format=%at -1)`)_
+
+* _**V**_
+
+  If non-empty, will pass `V=1` to all `make` invocations, making `make` output
+  verbose.
+
+* _**ADDITIONAL_GUIX_ENVIRONMENT_FLAGS**_
+
+  Additional flags to be passed to `guix environment`. For a fully-bootstrapped
+  build, set this to `--bootstrap --no-substitutes`. Note that a
+  fully-bootstrapped build will take quite a long time on the first run.
+
+## Tips and Tricks
+
+### Speeding up builds with substitute servers
+
+_This whole section is automatically done in the convenience
+[Dockerfiles][fanquake/guix-docker]_
+
+For those who are used to life in the fast _(and trustful)_ lane, you can use
+[substitute servers][guix/substitutes] to enable binary downloads of packages.
+
+> For those who only want to use substitutes from the official Guix build farm
+> and have authorized the build farm's signing key during Guix's installation,
+> you don't need to do anything.
+
+#### Authorize the signing keys
+
+For the official Guix build farm at https://ci.guix.gnu.org, run as root:
+
+```
+guix archive --authorize < ~root/.config/guix/current/share/guix/ci.guix.gnu.org.pub
+```
+
+For dongcarl's substitute server at https://guix.carldong.io, run as root:
+
+```sh
+wget -qO- 'https://guix.carldong.io/signing-key.pub' | guix archive --authorize
+```
+
+#### Use the substitute servers
+
+The official Guix build farm at https://ci.guix.gnu.org is automatically used
+unless the `--no-substitutes` flag is supplied.
+
+This can be overridden for all `guix` invocations by passing the
+`--substitute-urls` option to your invocation of `guix-daemon`. This can also be
+overridden on a call-by-call basis by passing the same `--substitute-urls`
+option to client tools such at `guix environment`.
+
+To use dongcarl's substitute server for Bitcoin Core builds after having
+[authorized his signing key](#authorize-the-signing-keys):
+
+```
+export ADDITIONAL_GUIX_ENVIRONMENT_FLAGS='--substitute-urls="https://guix.carldong.io https://ci.guix.gnu.org"'
+```
+
+## FAQ
+
+### How can I trust the binary installation?
+
+As mentioned at the bottom of [this manual page][guix/bin-install]:
+
+> The binary installation tarballs can be (re)produced and verified simply by
+> running the following command in the Guix source tree:
+>
+>     make guix-binary.x86_64-linux.tar.xz
+
+### When will Guix be packaged in debian?
+
+Vagrant Cascadian has been making good progress on this
+[here][debian/guix-package]. We have all the pieces needed to put up an APT
+repository and will likely put one up soon.
+
+[b17e]: http://bootstrappable.org/
+[r12e/source-date-epoch]: https://reproducible-builds.org/docs/source-date-epoch/
+
+[guix/install.sh]: https://git.savannah.gnu.org/cgit/guix.git/plain/etc/guix-install.sh
+[guix/bin-install]: https://www.gnu.org/software/guix/manual/en/html_node/Binary-Installation.html
+[guix/env-setup]: https://www.gnu.org/software/guix/manual/en/html_node/Build-Environment-Setup.html
+[guix/substitutes]: https://www.gnu.org/software/guix/manual/en/html_node/Substitutes.html
+[guix/substitute-server-auth]: https://www.gnu.org/software/guix/manual/en/html_node/Substitute-Server-Authorization.html
+[guix/inferiors]: https://www.gnu.org/software/guix/manual/en/html_node/Inferiors.html
+[guix/channels]: https://www.gnu.org/software/guix/manual/en/html_node/Channels.html
+
+[debian/guix-package]: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=850644
+[fanquake/guix-docker]: https://github.com/fanquake/core-review/tree/master/guix
diff --git a/contrib/guix/guix-build.sh b/contrib/guix/guix-build.sh
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+++ b/contrib/guix/guix-build.sh
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+#!/usr/bin/env bash
+export LC_ALL=C
+set -e -o pipefail
+
+# Determine the maximum number of jobs to run simultaneously (overridable by
+# environment)
+MAX_JOBS="${MAX_JOBS:-$(nproc)}"
+
+# Download the depends sources now as we won't have internet access in the build
+# container
+make -C "${PWD}/depends" -j"$MAX_JOBS" download ${V:+V=1} ${SOURCES_PATH:+SOURCES_PATH="$SOURCES_PATH"}
+
+# Determine the reference time used for determinism (overridable by environment)
+SOURCE_DATE_EPOCH="${SOURCE_DATE_EPOCH:-$(git log --format=%at -1)}"
+
+# Deterministically build Bitcoin Core for HOSTs (overriable by environment)
+for host in ${HOSTS=i686-linux-gnu x86_64-linux-gnu arm-linux-gnueabihf aarch64-linux-gnu riscv64-linux-gnu}; do
+
+    # Display proper warning when the user interrupts the build
+    trap 'echo "** INT received while building ${host}, you may want to clean up the relevant output and distsrc-* directories before rebuilding"' INT
+
+    # Run the build script 'contrib/guix/build.sh' in the build container
+    # specified by 'contrib/guix/manifest.scm'
+    # shellcheck disable=SC2086
+    guix environment --manifest="${PWD}/contrib/guix/manifest.scm" \
+                     --container \
+                     --pure \
+                     --no-cwd \
+                     --share="$PWD"=/bitcoin \
+                     ${SOURCES_PATH:+--share="$SOURCES_PATH"} \
+                     ${ADDITIONAL_GUIX_ENVIRONMENT_FLAGS} \
+                     -- env HOST="$host" \
+                            MAX_JOBS="$MAX_JOBS" \
+                            SOURCE_DATE_EPOCH="${SOURCE_DATE_EPOCH:?unable to determine value}" \
+                            ${V:+V=1} \
+                            ${SOURCES_PATH:+SOURCES_PATH="$SOURCES_PATH"} \
+                          bash -c "cd /bitcoin && bash contrib/guix/libexec/build.sh"
+
+done
diff --git a/contrib/guix/libexec/build.sh b/contrib/guix/libexec/build.sh
new file mode 100644
index 0000000000..56b972a5cb
--- /dev/null
+++ b/contrib/guix/libexec/build.sh
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+#!/usr/bin/env bash
+export LC_ALL=C
+set -e -o pipefail
+
+# Check that environment variables assumed to be set by the environment are set
+echo "Building for platform triple ${HOST:?not set} with reference timestamp ${SOURCE_DATE_EPOCH:?not set}..."
+echo "At most ${MAX_JOBS:?not set} jobs will run at once..."
+
+#####################
+# Environment Setup #
+#####################
+
+# The depends folder also serves as a base-prefix for depends packages for
+# $HOSTs after successfully building.
+BASEPREFIX="${PWD}/depends"
+
+# Setup an output directory for our build
+OUTDIR="${OUTDIR:-${PWD}/output}"
+[ -e "$OUTDIR" ] || mkdir -p "$OUTDIR"
+
+# Setup the directory where our Bitcoin Core build for HOST will occur
+DISTSRC="${DISTSRC:-${PWD}/distsrc-${HOST}}"
+if [ -e "$DISTSRC" ]; then
+    echo "DISTSRC directory '${DISTSRC}' exists, probably because of previous builds... Aborting..."
+    exit 1
+else
+    mkdir -p "$DISTSRC"
+fi
+
+# Given a package name and an output name, return the path of that output in our
+# current guix environment
+store_path() {
+    grep --extended-regexp "/[^-]{32}-${1}-cross-${HOST}-[^-]+${2:+-${2}}" "${GUIX_ENVIRONMENT}/manifest" \
+        | head --lines=1 \
+        | sed --expression='s|^[[:space:]]*"||' \
+              --expression='s|"[[:space:]]*$||'
+}
+
+# Determine output paths to use in CROSS_* environment variables
+CROSS_GLIBC="$(store_path glibc)"
+CROSS_GLIBC_STATIC="$(store_path glibc static)"
+CROSS_KERNEL="$(store_path linux-libre-headers)"
+CROSS_GCC="$(store_path gcc)"
+
+# Set environment variables to point Guix's cross-toolchain to the right
+# includes/libs for $HOST
+export CROSS_C_INCLUDE_PATH="${CROSS_GCC}/include:${CROSS_GLIBC}/include:${CROSS_KERNEL}/include"
+export CROSS_CPLUS_INCLUDE_PATH="${CROSS_GCC}/include/c++:${CROSS_GLIBC}/include:${CROSS_KERNEL}/include"
+export CROSS_LIBRARY_PATH="${CROSS_GLIBC}/lib:${CROSS_GLIBC_STATIC}/lib:${CROSS_GCC}/lib:${CROSS_GCC}/${HOST}/lib:${CROSS_KERNEL}/lib"
+
+# Disable Guix ld auto-rpath behavior
+export GUIX_LD_WRAPPER_DISABLE_RPATH=yes
+
+# Make /usr/bin if it doesn't exist
+[ -e /usr/bin ] || mkdir -p /usr/bin
+
+# Symlink file and env to a conventional path
+[ -e /usr/bin/file ] || ln -s --no-dereference "$(command -v file)" /usr/bin/file
+[ -e /usr/bin/env ]  || ln -s --no-dereference "$(command -v env)"  /usr/bin/env
+
+# Determine the correct value for -Wl,--dynamic-linker for the current $HOST
+glibc_dynamic_linker=$(
+    case "$HOST" in
+        i686-linux-gnu)      echo /lib/ld-linux.so.2 ;;
+        x86_64-linux-gnu)    echo /lib64/ld-linux-x86-64.so.2 ;;
+        arm-linux-gnueabihf) echo /lib/ld-linux-armhf.so.3 ;;
+        aarch64-linux-gnu)   echo /lib/ld-linux-aarch64.so.1 ;;
+        riscv64-linux-gnu)   echo /lib/ld-linux-riscv64-lp64d.so.1 ;;
+        *)                   exit 1 ;;
+    esac
+)
+
+# Environment variables for determinism
+export QT_RCC_TEST=1
+export QT_RCC_SOURCE_DATE_OVERRIDE=1
+export TAR_OPTIONS="--owner=0 --group=0 --numeric-owner --mtime='@${SOURCE_DATE_EPOCH}' --sort=name"
+export TZ="UTC"
+
+####################
+# Depends Building #
+####################
+
+# Build the depends tree, overriding variables that assume multilib gcc
+make -C depends --jobs="$MAX_JOBS" HOST="$HOST" \
+                                   ${V:+V=1} \
+                                   ${SOURCES_PATH+SOURCES_PATH="$SOURCES_PATH"} \
+                                   i686_linux_CC=i686-linux-gnu-gcc \
+                                   i686_linux_CXX=i686-linux-gnu-g++ \
+                                   i686_linux_AR=i686-linux-gnu-ar \
+                                   i686_linux_RANLIB=i686-linux-gnu-ranlib \
+                                   i686_linux_NM=i686-linux-gnu-nm \
+                                   i686_linux_STRIP=i686-linux-gnu-strip \
+                                   x86_64_linux_CC=x86_64-linux-gnu-gcc \
+                                   x86_64_linux_CXX=x86_64-linux-gnu-g++ \
+                                   x86_64_linux_AR=x86_64-linux-gnu-ar \
+                                   x86_64_linux_RANLIB=x86_64-linux-gnu-ranlib \
+                                   x86_64_linux_NM=x86_64-linux-gnu-nm \
+                                   x86_64_linux_STRIP=x86_64-linux-gnu-strip \
+                                   qt_config_opts_i686_linux='-platform linux-g++ -xplatform bitcoin-linux-g++'
+
+
+###########################
+# Source Tarball Building #
+###########################
+
+# Create the source tarball and move it to "${OUTDIR}/src" if not already there
+if [ -z "$(find "${OUTDIR}/src" -name 'bitcoin-*.tar.gz')" ]; then
+    ./autogen.sh
+    env CONFIG_SITE="${BASEPREFIX}/${HOST}/share/config.site" ./configure --prefix=/
+    make dist GZIP_ENV='-9n' ${V:+V=1}
+    mkdir -p "${OUTDIR}/src"
+    mv "$(find "${PWD}" -name 'bitcoin-*.tar.gz')" "${OUTDIR}/src/"
+fi
+
+# Determine the full path to our source tarball
+SOURCEDIST="$(find "${OUTDIR}/src" -name 'bitcoin-*.tar.gz')"
+# Determine our distribution name (e.g. bitcoin-0.18.0)
+DISTNAME="$(basename "$SOURCEDIST" '.tar.gz')"
+
+###########################
+# Binary Tarball Building #
+###########################
+
+# Create a spec file to normalize ssp linking behaviour
+spec_file="$(mktemp)"
+cat << EOF > "$spec_file"
+*link_ssp:
+%{fstack-protector|fstack-protector-all|fstack-protector-strong|fstack-protector-explicit:}
+EOF
+
+# Similar flags to Gitian
+CONFIGFLAGS="--enable-glibc-back-compat --enable-reduce-exports --disable-bench --disable-gui-tests"
+HOST_CFLAGS="-O2 -g -specs=${spec_file} -ffile-prefix-map=${PWD}=."
+HOST_CXXFLAGS="-O2 -g -specs=${spec_file} -ffile-prefix-map=${PWD}=."
+HOST_LDFLAGS="-Wl,--as-needed -Wl,--dynamic-linker=$glibc_dynamic_linker -static-libstdc++"
+
+# Make $HOST-specific native binaries from depends available in $PATH
+export PATH="${BASEPREFIX}/${HOST}/native/bin:${PATH}"
+(
+    cd "$DISTSRC"
+
+    # Extract the source tarball
+    tar --strip-components=1 -xf "${SOURCEDIST}"
+
+    # Configure this DISTSRC for $HOST
+    # shellcheck disable=SC2086
+    env CONFIG_SITE="${BASEPREFIX}/${HOST}/share/config.site" \
+        ./configure --prefix=/ \
+                    --disable-ccache \
+                    --disable-maintainer-mode \
+                    --disable-dependency-tracking \
+                    ${CONFIGFLAGS} \
+                    CFLAGS="${HOST_CFLAGS}" \
+                    CXXFLAGS="${HOST_CXXFLAGS}" \
+                    LDFLAGS="${HOST_LDFLAGS}"
+
+    sed -i.old 's/-lstdc++ //g' config.status libtool src/univalue/config.status src/univalue/libtool
+
+    # Build Bitcoin Core
+    make --jobs="$MAX_JOBS" ${V:+V=1}
+
+    # Perform basic ELF security checks on a series of executables.
+    make -C src --jobs=1 check-security ${V:+V=1}
+    # Check that executables only contain allowed gcc, glibc and libstdc++
+    # version symbols for Linux distro back-compatibility.
+    make -C src --jobs=1 check-symbols  ${V:+V=1}
+
+    # Setup the directory where our Bitcoin Core build for HOST will be
+    # installed. This directory will also later serve as the input for our
+    # binary tarballs.
+    INSTALLPATH="${PWD}/installed/${DISTNAME}"
+    mkdir -p "${INSTALLPATH}"
+    # Install built Bitcoin Core to $INSTALLPATH
+    make install DESTDIR="${INSTALLPATH}" ${V:+V=1}
+    (
+        cd installed
+
+        # Prune libtool and object archives
+        find . -name "lib*.la" -delete
+        find . -name "lib*.a" -delete
+
+        # Prune pkg-config files
+        rm -r "${DISTNAME}/lib/pkgconfig"
+
+        # Split binaries and libraries from their debug symbols
+        {
+            find "${DISTNAME}/bin" -type f -executable -print0
+            find "${DISTNAME}/lib" -type f -print0
+        } | xargs -0 -n1 -P"$MAX_JOBS" -I{} "${DISTSRC}/contrib/devtools/split-debug.sh" {} {} {}.dbg
+
+        cp "${DISTSRC}/doc/README.md" "${DISTNAME}/"
+
+        # Finally, deterministically produce {non-,}debug binary tarballs ready
+        # for release
+        find "${DISTNAME}" -not -name "*.dbg" -print0 \
+            | sort --zero-terminated \
+            | tar --create --no-recursion --mode='u+rw,go+r-w,a+X' --null --files-from=- \
+            | gzip -9n > "${OUTDIR}/${DISTNAME}-${HOST}.tar.gz" \
+            || ( rm -f "${OUTDIR}/${DISTNAME}-${HOST}.tar.gz" && exit 1 )
+        find "${DISTNAME}" -name "*.dbg" -print0 \
+            | sort --zero-terminated \
+            | tar --create --no-recursion --mode='u+rw,go+r-w,a+X' --null --files-from=- \
+            | gzip -9n > "${OUTDIR}/${DISTNAME}-${HOST}-debug.tar.gz" \
+            || ( rm -f "${OUTDIR}/${DISTNAME}-${HOST}-debug.tar.gz" && exit 1 )
+    )
+)
diff --git a/contrib/guix/manifest.scm b/contrib/guix/manifest.scm
new file mode 100644
index 0000000000..e661480cd8
--- /dev/null
+++ b/contrib/guix/manifest.scm
@@ -0,0 +1,155 @@
+(define-module (bitcoin)
+  #:use-module (gnu)
+  #:use-module (gnu packages)
+  #:use-module (gnu packages autotools)
+  #:use-module (gnu packages base)
+  #:use-module (gnu packages bash)
+  #:use-module (gnu packages check)
+  #:use-module (gnu packages commencement)
+  #:use-module (gnu packages compression)
+  #:use-module (gnu packages cross-base)
+  #:use-module (gnu packages file)
+  #:use-module (gnu packages gawk)
+  #:use-module (gnu packages gcc)
+  #:use-module (gnu packages linux)
+  #:use-module (gnu packages perl)
+  #:use-module (gnu packages pkg-config)
+  #:use-module (gnu packages python)
+  #:use-module (gnu packages shells)
+  #:use-module (guix build-system trivial)
+  #:use-module (guix gexp)
+  #:use-module (guix packages)
+  #:use-module (guix profiles)
+  #:use-module (guix utils))
+
+(define (make-ssp-fixed-gcc xgcc)
+  "Given a XGCC package, return a modified package that uses the SSP function
+from glibc instead of from libssp.so. Taken from:
+http://www.linuxfromscratch.org/hlfs/view/development/chapter05/gcc-pass1.html"
+  (package
+   (inherit xgcc)
+   (arguments
+    (substitute-keyword-arguments (package-arguments xgcc)
+      ((#:make-flags flags)
+       `(cons "gcc_cv_libc_provides_ssp=yes" ,flags))))))
+
+(define (make-gcc-rpath-link xgcc)
+  "Given a XGCC package, return a modified package that replace each instance of
+-rpath in the default system spec that's inserted by Guix with -rpath-link"
+  (package
+   (inherit xgcc)
+   (arguments
+    (substitute-keyword-arguments (package-arguments xgcc)
+      ((#:phases phases)
+       `(modify-phases ,phases
+          (add-after 'pre-configure 'replace-rpath-with-rpath-link
+            (lambda _
+              (substitute* (cons "gcc/config/rs6000/sysv4.h"
+                                 (find-files "gcc/config"
+                                             "^gnu-user.*\\.h$"))
+                (("-rpath=") "-rpath-link="))
+              #t))))))))
+
+(define (make-cross-toolchain target
+                              base-gcc-for-libc
+                              base-kernel-headers
+                              base-libc
+                              base-gcc)
+  "Create a cross-compilation toolchain package for TARGET"
+  (let* ((xbinutils (cross-binutils target))
+         ;; 1. Build a cross-compiling gcc without targeting any libc, derived
+         ;; from BASE-GCC-FOR-LIBC
+         (xgcc-sans-libc (cross-gcc target
+                                    #:xgcc base-gcc-for-libc
+                                    #:xbinutils xbinutils))
+         ;; 2. Build cross-compiled kernel headers with XGCC-SANS-LIBC, derived
+         ;; from BASE-KERNEL-HEADERS
+         (xkernel (cross-kernel-headers target
+                                        base-kernel-headers
+                                        xgcc-sans-libc
+                                        xbinutils))
+         ;; 3. Build a cross-compiled libc with XGCC-SANS-LIBC and XKERNEL,
+         ;; derived from BASE-LIBC
+         (xlibc (cross-libc target
+                            base-libc
+                            xgcc-sans-libc
+                            xbinutils
+                            xkernel))
+         ;; 4. Build a cross-compiling gcc targeting XLIBC, derived from
+         ;; BASE-GCC
+         (xgcc (cross-gcc target
+                          #:xgcc base-gcc
+                          #:xbinutils xbinutils
+                          #:libc xlibc)))
+    ;; Define a meta-package that propagates the resulting XBINUTILS, XLIBC, and
+    ;; XGCC
+    (package
+      (name (string-append target "-toolchain"))
+      (version (package-version xgcc))
+      (source #f)
+      (build-system trivial-build-system)
+      (arguments '(#:builder (begin (mkdir %output) #t)))
+      (propagated-inputs
+       `(("binutils" ,xbinutils)
+         ("libc" ,xlibc)
+         ("libc:static" ,xlibc "static")
+         ("gcc" ,xgcc)))
+      (synopsis (string-append "Complete GCC tool chain for " target))
+      (description (string-append "This package provides a complete GCC tool
+chain for " target " development."))
+      (home-page (package-home-page xgcc))
+      (license (package-license xgcc)))))
+
+(define* (make-bitcoin-cross-toolchain target
+                                  #:optional
+                                  (base-gcc-for-libc gcc-5)
+                                  (base-kernel-headers linux-libre-headers-4.19)
+                                  (base-libc glibc-2.27)
+                                  (base-gcc (make-gcc-rpath-link
+                                             (make-ssp-fixed-gcc gcc-9))))
+  "Convienience wrapper around MAKE-CROSS-TOOLCHAIN with default values
+desirable for building Bitcoin Core release binaries."
+  (make-cross-toolchain target
+                   base-gcc-for-libc
+                   base-kernel-headers
+                   base-libc
+                   base-gcc))
+
+(packages->manifest
+ (list ;; The Basics
+       bash
+       tcsh
+       which
+       coreutils
+       util-linux
+       ;; File(system) inspection
+       file
+       grep
+       diffutils
+       findutils
+       ;; File transformation
+       patch
+       gawk
+       sed
+       ;; Compression and archiving
+       tar
+       bzip2
+       gzip
+       xz
+       zlib
+       ;; Build tools
+       gnu-make
+       libtool
+       autoconf
+       automake
+       pkg-config
+       ;; Scripting
+       perl
+       python
+       ;; Toolchains
+       (make-gcc-toolchain gcc-9 glibc-2.27)
+       (make-bitcoin-cross-toolchain "riscv64-linux-gnu" gcc-8)
+       (make-bitcoin-cross-toolchain "x86_64-linux-gnu")
+       (make-bitcoin-cross-toolchain "i686-linux-gnu")
+       (make-bitcoin-cross-toolchain "aarch64-linux-gnu")
+       (make-bitcoin-cross-toolchain "arm-linux-gnueabihf" gcc-6)))