diff --git a/stream/rar.c b/stream/rar.c
index 31211c777b..ec68bcbfa2 100644
--- a/stream/rar.c
+++ b/stream/rar.c
@@ -25,6 +25,9 @@
  * 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 ad1f843f35..064c805b6c 100644
--- a/waftools/detections/compiler.py
+++ b/waftools/detections/compiler.py
@@ -17,7 +17,8 @@ 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_GNU_SOURCE",
+    ctx.env.CFLAGS += ["-D_ISOC99_SOURCE", "-D_POSIX_C_SOURCE=200809L",
+                       "-D_BSD_SOURCE", "-D_XOPEN_SOURCE=700",
                        "-D_LARGEFILE_SOURCE", "-D_FILE_OFFSET_BITS=64",
                        "-D_LARGEFILE64_SOURCE",
                        "-std=c99", "-Wall"]