Merge #15146: Solve SmartOS FD_ZERO build issue

b4fd0ca9be14c81023db759c405c0f67cfa78166 Include cstring for sanity_test_fdelt if required (Ben Woosley)
7fb886b1b1110de4c79478ac094e64cdcb81f3c8 [moveonly] Split glibc sanity_test_fdelt out (Ben Woosley)

Pull request description:

  SmartOS FD_ZERO is implemented in a way that requires
  an external declaration of memcpy. We can not simply
  include cstring in the existing file because
  sanity_test_memcpy is attempting to replace memcpy.

  Instead split glibc_sanity into fdelt and memcpy files,
  and include <cstring> in glibc_sanity/fdelt.cpp.

  Fixes #13581, see also #13619

ACKs for top commit:
  laanwj:
    Code review an lightly tested (but not on SmartOS) ACK b4fd0ca9be14c81023db759c405c0f67cfa78166

Tree-SHA512: 231306da291ad9eca8ba91bea1e9c27b6c2e96e484d1602e1c2cf27761202f9287ce0bc19fefd000943d2b449d0e5929cd39e2f7e09cf930d89fa520228ccbec

3 files changed, 29 insertions, 17 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index 8fc7f61d4b..1ef62a656d 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -484,6 +484,7 @@ libbitcoin_util_a_SOURCES = \
   support/lockedpool.cpp \
   chainparamsbase.cpp \
   clientversion.cpp \
+  compat/glibc_sanity_fdelt.cpp \
   compat/glibc_sanity.cpp \
   compat/glibcxx_sanity.cpp \
   compat/strnlen.cpp \
diff --git a/src/compat/glibc_sanity.cpp b/src/compat/glibc_sanity.cpp
index 1ef66e27b4..cc74f28899 100644
--- a/src/compat/glibc_sanity.cpp
+++ b/src/compat/glibc_sanity.cpp
@@ -1,4 +1,4 @@
-// Copyright (c) 2009-2018 The Bitcoin Core developers
+// Copyright (c) 2009-2019 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
@@ -9,7 +9,7 @@
 #include <cstddef>
 
 #if defined(HAVE_SYS_SELECT_H)
-#include <sys/select.h>
+bool sanity_test_fdelt();
 #endif
 
 extern "C" void* memcpy(void* a, const void* b, size_t c);
@@ -41,21 +41,6 @@ bool sanity_test_memcpy()
     }
     return true;
 }
-
-#if defined(HAVE_SYS_SELECT_H)
-// trigger: Call FD_SET to trigger __fdelt_chk. FORTIFY_SOURCE must be defined
-//   as >0 and optimizations must be set to at least -O2.
-// test: Add a file descriptor to an empty fd_set. Verify that it has been
-//   correctly added.
-bool sanity_test_fdelt()
-{
-    fd_set fds;
-    FD_ZERO(&fds);
-    FD_SET(0, &fds);
-    return FD_ISSET(0, &fds);
-}
-#endif
-
 } // namespace
 
 bool glibc_sanity_test()
diff --git a/src/compat/glibc_sanity_fdelt.cpp b/src/compat/glibc_sanity_fdelt.cpp
new file mode 100644
index 0000000000..87140d0c71
--- /dev/null
+++ b/src/compat/glibc_sanity_fdelt.cpp
@@ -0,0 +1,26 @@
+// Copyright (c) 2009-2019 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#if defined(HAVE_CONFIG_H)
+#include <config/bitcoin-config.h>
+#endif
+
+#if defined(HAVE_SYS_SELECT_H)
+#ifdef HAVE_CSTRING_DEPENDENT_FD_ZERO
+#include <cstring>
+#endif
+#include <sys/select.h>
+
+// trigger: Call FD_SET to trigger __fdelt_chk. FORTIFY_SOURCE must be defined
+//   as >0 and optimizations must be set to at least -O2.
+// test: Add a file descriptor to an empty fd_set. Verify that it has been
+//   correctly added.
+bool sanity_test_fdelt()
+{
+    fd_set fds;
+    FD_ZERO(&fds);
+    FD_SET(0, &fds);
+    return FD_ISSET(0, &fds);
+}
+#endif