Fix #294. Add -D_GNU_SOURCE when building under Cygwin
diff --git a/CMakeLists.txt b/CMakeLists.txt
index dfa8a65..8bfd21b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -91,6 +91,14 @@
cxx_feature_check(THREAD_SAFETY_ATTRIBUTES)
endif()
+ # On most UNIX like platforms g++ and clang++ define _GNU_SOURCE as a
+ # predefined macro, which turns on all of the wonderful libc extensions.
+ # However g++ doesn't do this in Cygwin so we have to define it ourselfs
+ # since we depend on GNU/POSIX/BSD extensions.
+ if (CYGWIN)
+ add_definitions(-D_GNU_SOURCE=1)
+ endif()
+
# Link time optimisation
if (BENCHMARK_ENABLE_LTO)
add_cxx_compiler_flag(-flto)
