diff --git a/CMakeLists.txt b/CMakeLists.txt
index dddb15b..631feb3 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -10,7 +10,7 @@ if( CMAKE_SIZEOF_VOID_P EQUAL 8 )
   #64 bits
   MESSAGE( STATUS "64 bits" )
   set(CMAKE_C_FLAGS_DEBUG "-ggdb -DLINUX -Dlinux -m64 -march=core2 -fPIC -D_REENTRANT -pthread")
-  set(CMAKE_C_FLAGS_RELEASE "-DLINUX -Dlinux -m64 -march=core2 -fPIC -D_REENTRANT -pthread")
+  set(CMAKE_C_FLAGS_RELEASE "-DLINUX -D_POSIX_SOURCE -Dlinux -m64 -march=core2 -fPIC -D_REENTRANT -pthread")
   set(CMAKE_CXX_FLAGS_DEBUG "-std=c++0x -fPIC -Wall -Wextra -ggdb -DLINUX -Dlinux -D_REENTRANT -malign-double -pthread")
   set(CMAKE_CXX_FLAGS_RELEASE "-std=c++0x -Wall -Wextra -fPIC -DLINUX -Dlinux -D_REENTRANT -malign-double -pthread -O3 -DNDEBUG")
   set(USRLIB_DIR "/usr/lib64/:/usr/local/lib64/")
--
libgit2 0.21.2