diff --git a/configure.ac b/configure.ac
index ff4bae88fb9..c7f72a59604 100644
--- a/configure.ac
+++ b/configure.ac
@@ -29,6 +29,8 @@ AC_ARG_WITH(nbpf-path, AS_HELP_STRING([--with-nbpf-path], [nBPF library custom p
 AC_ARG_WITH(lto-and-gold-linker, AS_HELP_STRING([--with-lto-and-gold-linker], [Build with LTO and Gold linker]))
 AC_ARG_ENABLE(debug-build, AS_HELP_STRING([--enable-debug-build], [Enable debug build (`-g` flag)]),[enable_debugbuild=$enableval],[enable_debugbuild=no])
 
+NDPI_CFLAGS="${NDPI_CFLAGS} -D_DEFAULT_SOURCE=1 -D_GNU_SOURCE=1"
+
 AS_IF([test "x$enable_fuzztargets" = "xyes"], [
   BUILD_FUZZTARGETS=1
   NDPI_CFLAGS="${NDPI_CFLAGS} -DFUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION"
diff --git a/example/ndpiReader.c b/example/ndpiReader.c
index 19f53d176c5..f7482ca65bb 100644
--- a/example/ndpiReader.c
+++ b/example/ndpiReader.c
@@ -21,9 +21,6 @@
 #include "ndpi_config.h"
 
 #ifdef __linux__
-#ifndef _GNU_SOURCE
-#define _GNU_SOURCE
-#endif
 #include <sched.h>
 #endif
 
diff --git a/src/lib/ndpi_classify.c b/src/lib/ndpi_classify.c
index 3dba2207e96..538eb2b8234 100644
--- a/src/lib/ndpi_classify.c
+++ b/src/lib/ndpi_classify.c
@@ -41,8 +41,6 @@
  *
  */
 
-#define _GNU_SOURCE
-
 #include <stdio.h>
 #include <ctype.h>
 // #include <sys/time.h>
diff --git a/src/lib/third_party/src/roaring.c b/src/lib/third_party/src/roaring.c
index ab95ab6e8b3..f8ee417dab7 100644
--- a/src/lib/third_party/src/roaring.c
+++ b/src/lib/third_party/src/roaring.c
@@ -81,9 +81,6 @@
 #ifndef INCLUDE_PORTABILITY_H_
 #define INCLUDE_PORTABILITY_H_
 
-#ifndef _GNU_SOURCE
-#define _GNU_SOURCE 1
-#endif // _GNU_SOURCE
 #ifndef __STDC_FORMAT_MACROS
 #define __STDC_FORMAT_MACROS 1
 #endif // __STDC_FORMAT_MACROS
diff --git a/tests/performance/gcrypt.c b/tests/performance/gcrypt.c
index febc18f1b49..e6f59060b17 100644
--- a/tests/performance/gcrypt.c
+++ b/tests/performance/gcrypt.c
@@ -1,5 +1,3 @@
-#define _DEFAULT_SOURCE
-#define _GNU_SOURCE
 #include <stdio.h>
 #include <stdint.h>
 #include <stdlib.h>
diff --git a/tests/unit/unit.c b/tests/unit/unit.c
index 5212c768e40..37ed1315da8 100644
--- a/tests/unit/unit.c
+++ b/tests/unit/unit.c
@@ -19,9 +19,6 @@
  */
 
 #ifdef __linux__
-#ifndef _GNU_SOURCE
-#define _GNU_SOURCE
-#endif
 #include <sched.h>
 #endif /* linux */