Move the _GNU_SOURCE def

Author: chriso

CMakeLists.txt

@@ -36,4 +36,4 @@ else ()
   set (FLAGS "-O3 -march=native")
 endif()
 
-set (CMAKE_C_FLAGS "-std=c99 -Wall -pedantic -g ${FLAGS}")
+set (CMAKE_C_FLAGS "-std=c99 -Wall -pedantic -g -D_GNU_SOURCE ${FLAGS}")

block.c

@@ -1,4 +1,3 @@
-#define _GNU_SOURCE
 #include <stdlib.h>
 #include <string.h>
 #include <stdint.h>