Merge #11702: [build] Add a script for installing db4

6e4cdd6 [docs] Add reference to install_db4.sh in OS X build instructions (James O'Beirne)
af9103e [build] Add a script for installing db4 (James O'Beirne)

Pull request description:

  Instead of maintaining rote instructions for building BerkeleyDB in `doc/build-{unix,openbsd}.md`, reference a script that does the same thing and can be called from unanticipated contexts, e.g. Docker builds.

  The script was written with portability in mind, though I haven't tested it on openbsd.

  I wasn't sure if we wanted to create a separate directory for this sort of thing (e.g. `contrib/install`) so I just stuck it in `contrib/`; happy to move it around if anyone has another preference.

Tree-SHA512: d2fc83c065d083458c448e6041e5e9ef67f8165974925560a83881d22d1e9448ea3dd4f7a38196800a8cd6dcf206208a2d6d12417bfe094902d4754e4ca67f18

3 files changed, 29 insertions, 43 deletions

diff --git a/doc/build-openbsd.md b/doc/build-openbsd.md
index 760bb69b15..cd1d217b47 100644
--- a/doc/build-openbsd.md
+++ b/doc/build-openbsd.md
@@ -38,28 +38,17 @@ The default C++ compiler that comes with OpenBSD 6.2 is g++ 4.2.1. This version
 
 BerkeleyDB is only necessary for the wallet functionality. To skip this, pass `--disable-wallet` to `./configure`.
 
-See "Berkeley DB" in [build-unix.md](build-unix.md#berkeley-db) for instructions on how to build BerkeleyDB 4.8.
-You cannot use the BerkeleyDB library from ports, for the same reason as boost above (g++/libstd++ incompatibility).
+It is recommended to use Berkeley DB 4.8. You cannot use the BerkeleyDB library
+from ports, for the same reason as boost above (g++/libstd++ incompatibility).
+If you have to build it yourself, you can use [the installation script included
+in contrib/](contrib/install_db4.sh) like so
 
-```bash
-# Pick some path to install BDB to, here we create a directory within the bitcoin directory
-BITCOIN_ROOT=$(pwd)
-BDB_PREFIX="${BITCOIN_ROOT}/db4"
-mkdir -p $BDB_PREFIX
-
-# Fetch the source and verify that it is not tampered with
-curl -o db-4.8.30.NC.tar.gz 'http://download.oracle.com/berkeley-db/db-4.8.30.NC.tar.gz'
-echo '12edc0df75bf9abd7f82f821795bcee50f42cb2e5f76a6a281b85732798364ef  db-4.8.30.NC.tar.gz' | sha256 -c
-# MUST output: (SHA256) db-4.8.30.NC.tar.gz: OK
-tar -xzf db-4.8.30.NC.tar.gz
-
-# Build the library and install to specified prefix
-cd db-4.8.30.NC/build_unix/
-#  Note: Do a static build so that it can be embedded into the executable, instead of having to find a .so at runtime
-../dist/configure --enable-cxx --disable-shared --with-pic --prefix=$BDB_PREFIX CC=egcc CXX=eg++ CPP=ecpp
-make install # do NOT use -jX, this is broken
+```shell
+./contrib/install_db4.sh `pwd` CC=egcc CXX=eg++ CPP=ecpp
 ```
 
+from the root of the repository.
+
 ### Resource limits
 
 The standard ulimit restrictions in OpenBSD are very strict:
diff --git a/doc/build-osx.md b/doc/build-osx.md
index 836c856a64..6f08562ff8 100644
--- a/doc/build-osx.md
+++ b/doc/build-osx.md
@@ -26,6 +26,20 @@ If you want to build the disk image with `make deploy` (.dmg / optional), you ne
 
 NOTE: Building with Qt4 is still supported, however, could result in a broken UI. Building with Qt5 is recommended.
 
+Berkeley DB
+-----------
+It is recommended to use Berkeley DB 4.8. If you have to build it yourself,
+you can use [the installation script included in contrib/](contrib/install_db4.sh)
+like so
+
+```shell
+./contrib/install_db4.sh .
+```
+
+from the root of the repository.
+
+**Note**: You only need Berkeley DB if the wallet is enabled (see the section *Disable-Wallet mode* below).
+
 Build Bitcoin Core
 ------------------------
 
diff --git a/doc/build-unix.md b/doc/build-unix.md
index 8a102abaea..5d3329e2cf 100644
--- a/doc/build-unix.md
+++ b/doc/build-unix.md
@@ -165,33 +165,16 @@ turned off by default.  See the configure options for upnp behavior desired:
 
 Berkeley DB
 -----------
-It is recommended to use Berkeley DB 4.8. If you have to build it yourself:
+It is recommended to use Berkeley DB 4.8. If you have to build it yourself,
+you can use [the installation script included in contrib/](contrib/install_db4.sh)
+like so
 
-```bash
-BITCOIN_ROOT=$(pwd)
-
-# Pick some path to install BDB to, here we create a directory within the bitcoin directory
-BDB_PREFIX="${BITCOIN_ROOT}/db4"
-mkdir -p $BDB_PREFIX
-
-# Fetch the source and verify that it is not tampered with
-wget 'http://download.oracle.com/berkeley-db/db-4.8.30.NC.tar.gz'
-echo '12edc0df75bf9abd7f82f821795bcee50f42cb2e5f76a6a281b85732798364ef  db-4.8.30.NC.tar.gz' | sha256sum -c
-# -> db-4.8.30.NC.tar.gz: OK
-tar -xzvf db-4.8.30.NC.tar.gz
-
-# Build the library and install to our prefix
-cd db-4.8.30.NC/build_unix/
-#  Note: Do a static build so that it can be embedded into the executable, instead of having to find a .so at runtime
-../dist/configure --enable-cxx --disable-shared --with-pic --prefix=$BDB_PREFIX
-make install
-
-# Configure Bitcoin Core to use our own-built instance of BDB
-cd $BITCOIN_ROOT
-./autogen.sh
-./configure LDFLAGS="-L${BDB_PREFIX}/lib/" CPPFLAGS="-I${BDB_PREFIX}/include/" # (other args...)
+```shell
+./contrib/install_db4.sh `pwd`
 ```
 
+from the root of the repository.
+
 **Note**: You only need Berkeley DB if the wallet is enabled (see the section *Disable-Wallet mode* below).
 
 Boost