cmake: do not bind to any particular POSIX C standard

This caused build failures on FreeBSD. Defining _POSIX_C_SOURCE to
a particular version will disable common non-POSIX extensions like
PF_UNIX, and on some systems will also disable features of later
POSIX versions, like IPv6. If we don't ask for a specific version,
we'll get some sort of sensible default.

Bug: https://bugs.freedesktop.org/show_bug.cgi?id=66257
Signed-off-by: Chengwei Yang <chengwei.yang@intel.com>
[made the commit message more concise -smcv]
Reviewed-by: Simon McVittie <simon.mcvittie@collabora.co.uk>

diff --git a/cmake/CMakeLists.txt b/cmake/CMakeLists.txt
index f25e55d..aecc74c 100644 (file)
--- a/cmake/CMakeLists.txt
+++ b/cmake/CMakeLists.txt
@@ -103,7 +103,7 @@ find_package(EXPAT)
 find_package(X11)
 
 # analogous to AC_USE_SYSTEM_EXTENSIONS in configure.ac
-add_definitions(-D_POSIX_C_SOURCE=199309L -D_GNU_SOURCE)
+add_definitions(-D_GNU_SOURCE)
 
 # do config checks
 INCLUDE(ConfigureChecks.cmake)