diff --git a/stream/rar.c b/stream/rar.c
index ec68bcbfa2..31211c777b 100644
--- a/stream/rar.c
+++ b/stream/rar.c
@@ -25,9 +25,6 @@
  * Preamble
  *****************************************************************************/
 
-// needed for asprintf()
-#define _GNU_SOURCE
-
 #include <assert.h>
 #include <limits.h>
 #include <stdio.h>
diff --git a/waftools/detections/compiler.py b/waftools/detections/compiler.py
index 96b7571a54..2d6f8c6d23 100644
--- a/waftools/detections/compiler.py
+++ b/waftools/detections/compiler.py
@@ -17,8 +17,7 @@ def __test_and_add_flags__(ctx, flags):
     ctx.env.CFLAGS += ctx.env.CFLAGS_compiler
 
 def __add_generic_flags__(ctx):
-    ctx.env.CFLAGS += ["-D_ISOC99_SOURCE", "-D_POSIX_C_SOURCE=200809L",
-                       "-D_BSD_SOURCE", "-D_XOPEN_SOURCE=700",
+    ctx.env.CFLAGS += ["-D_ISOC99_SOURCE", "-D_GNU_SOURCE",
                        "-D_LARGEFILE_SOURCE", "-D_FILE_OFFSET_BITS=64",
                        "-D_LARGEFILE64_SOURCE",
                        "-std=c99", "-Wall"]