In configure.ac, _DARWIN_C_SOURCE is defined to 900000L.
297 *-apple-darwin*) 298 AC_DEFINE(_DARWIN_C_SOURCE, 900000L, 299 Expose all libc features (__DARWIN_C_FULL).)
This was done as part of commit 654024081cfa103c87bb163b117ea3568171d408.
Later in configure.ac, -Werror is activated, to detect unknown attributes.
1077 # Following attribute tests depend on warnings to cause compile to fail, 1078 # so set -Werror temporarily. 1079 _gcc_cflags_save=$CFLAGS 1080 CFLAGS="$CFLAGS -Werror"
This is used to detect, for example, support for aligned.
The new cipher-gcm-intel-pclmul implementation does not work unless NEED_16BYTE_ALIGNED_CONTEXT is set (otherwise, there is a gpf accessing the context's key); this is, in turn, only set if HAVE_GCC_ATTRIBUTE_ALIGNED has been defined by the configure scripts. (BTW, that this is as brittle as it is--crashing at runtime if you are using a compiler that doesn't support this particular attribute--is maybe worth looking at: if aligned isn't supported, this new gcm implementation must be avoided, as the alignment is no longer merely a performance improvement.)
However, this test fails on macOS due to the following:
configure:16651: checking whether the GCC style aligned attribute is supported
configure:16662: clang -mmacosx-version-min=10.14 -isysroot /Applications/Xcode_11.3.1.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.15.sdk -resource-dir /Applications/Xcode_11.3.1.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/11.0.0 -B./ -fno-strict-return -arch x86_64 -target x86_64-apple-darwin18.5.0 -c -gfull -Os -fno-omit-frame-pointer -DPIC -fPIC -fno-ident -Werror conftest.c >&5
conftest.c:40:9: error: '_DARWIN_C_SOURCE' macro redefined [-Werror,-Wmacro-redefined]
#define _DARWIN_C_SOURCE 900000L
^
conftest.c:23:9: note: previous definition is here
#define _DARWIN_C_SOURCE 1
^
1 error generated.
configure:16662: $? = 1The issue is that configure already sets _DARWIN_C_SOURCE.
5638 printf "%s\n" "#define _DARWIN_C_SOURCE 1" >>confdefs.h
This is in specific.m4, and it is using AC_DEFINE's default of 1.
502 AC_DEFINE([_DARWIN_C_SOURCE])
This define is new, as of autoconf 2.71, and was not done by 2.69.
https://sources.debian.org/src/autoconf/2.71-1/lib/autoconf/specific.m4/#L502
FWIW, I've never heard of _DARWIN_C_SOURCE being non-1. If you grep Apple's SDK, it only ever checks whether this variable is defined.
Searching for 900000L, I believe there was some confusion with respect to _DARWIN_C_LEVEL: if you set _DARWIN_C_SOURCE, it sets __DARWIN_C_LEVEL to __DARWIN_C_FULL, which is 900000L; however, this is different from setting _DARWIN_C_SOURCE, which should only be set to 1.
/* * Set a single macro which will always be defined and can be used to determine * the appropriate namespace. For POSIX, these values will correspond to * _POSIX_C_SOURCE value. Currently there are two additional levels corresponding * to ANSI (_ANSI_SOURCE) and Darwin extensions (_DARWIN_C_SOURCE) */ #define __DARWIN_C_ANSI 010000L #define __DARWIN_C_FULL 900000L #if defined(_ANSI_SOURCE) #define __DARWIN_C_LEVEL __DARWIN_C_ANSI #elif defined(_POSIX_C_SOURCE) && !defined(_DARWIN_C_SOURCE) && !defined(_NONSTD_SOURCE) #define __DARWIN_C_LEVEL _POSIX_C_SOURCE #else #define __DARWIN_C_LEVEL __DARWIN_C_FULL #endif
If libgcrypt sets this variable to 1, everything works correctly again.
diff --git a/configure.ac b/configure.ac index a874c411..37947ecb 100644 --- a/configure.ac +++ b/configure.ac @@ -295,7 +295,7 @@ case "${host}" in m68k-atari-mint) ;; *-apple-darwin*) - AC_DEFINE(_DARWIN_C_SOURCE, 900000L, + AC_DEFINE(_DARWIN_C_SOURCE, 1, Expose all libc features (__DARWIN_C_FULL).) AC_DEFINE(USE_POSIX_SPAWN_FOR_TESTS, 1, [defined if we use posix_spawn in test program])
In the meantime, developers must pass -Wno-macro-redefined through CPPFLAGS as a workaround.