diff --git a/tools/Makefile b/tools/Makefile
index 33fad6b..6d45656 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -154,6 +154,7 @@ NOPEDOBJS := $(addprefix $(obj),$(NOPED_OBJ_FILES-y))
 #
 # Use native tools and options
 # Define __KERNEL_STRICT_NAMES to prevent typedef overlaps
+# Define _GNU_SOURCE to obtain the getline prototype from stdio.h
 #
 HOSTCPPFLAGS =	-include $(SRCTREE)/include/libfdt_env.h \
 		-idirafter $(SRCTREE)/include \
@@ -163,7 +164,8 @@ HOSTCPPFLAGS =	-include $(SRCTREE)/include/libfdt_env.h \
 		-I $(SRCTREE)/tools \
 		-DCONFIG_SYS_TEXT_BASE=$(CONFIG_SYS_TEXT_BASE) \
 		-DUSE_HOSTCC \
-		-D__KERNEL_STRICT_NAMES
+		-D__KERNEL_STRICT_NAMES \
+		-D_GNU_SOURCE
 
 
 all:	$(obj).depend $(BINS) $(LOGO-y) subdirs
diff --git a/tools/aisimage.c b/tools/aisimage.c
index cd89145..980bf2e 100644
--- a/tools/aisimage.c
+++ b/tools/aisimage.c
@@ -5,9 +5,6 @@
  * SPDX-License-Identifier:	GPL-2.0+ 
  */
 
-/* Required to obtain the getline prototype from stdio.h */
-#define _GNU_SOURCE
-
 #include "mkimage.h"
 #include "aisimage.h"
 #include <image.h>
diff --git a/tools/imximage.c b/tools/imximage.c
index c8a9ad5..cab208b 100644
--- a/tools/imximage.c
+++ b/tools/imximage.c
@@ -9,9 +9,6 @@
  * SPDX-License-Identifier:	GPL-2.0+ 
  */
 
-/* Required to obtain the getline prototype from stdio.h */
-#define _GNU_SOURCE
-
 #include "mkimage.h"
 #include <image.h>
 #include "imximage.h"
diff --git a/tools/kwbimage.c b/tools/kwbimage.c
index d08e498..1df6b20 100644
--- a/tools/kwbimage.c
+++ b/tools/kwbimage.c
@@ -6,9 +6,6 @@
  * SPDX-License-Identifier:	GPL-2.0+
  */
 
-/* Required to obtain the getline prototype from stdio.h */
-#define _GNU_SOURCE
-
 #include "mkimage.h"
 #include <image.h>
 #include "kwbimage.h"
diff --git a/tools/mkenvimage.c b/tools/mkenvimage.c
index f685ff2..bbd3041 100644
--- a/tools/mkenvimage.c
+++ b/tools/mkenvimage.c
@@ -9,9 +9,6 @@
  * SPDX-License-Identifier:	GPL-2.0+
  */
 
-/* We want the GNU version of basename() */
-#define _GNU_SOURCE
-
 #include <errno.h>
 #include <fcntl.h>
 #include <stdio.h>
diff --git a/tools/omapimage.c b/tools/omapimage.c
index d4d77d8..00853dd 100644
--- a/tools/omapimage.c
+++ b/tools/omapimage.c
@@ -14,9 +14,6 @@
  * SPDX-License-Identifier:	GPL-2.0+ 
  */
 
-/* Required to obtain the getline prototype from stdio.h */
-#define _GNU_SOURCE
-
 #include "mkimage.h"
 #include <image.h>
 #include "omapimage.h"
diff --git a/tools/pblimage.c b/tools/pblimage.c
index 4542a9c..bac5faf 100644
--- a/tools/pblimage.c
+++ b/tools/pblimage.c
@@ -3,8 +3,6 @@
  *
  * SPDX-License-Identifier:	GPL-2.0+
  */
-#define _GNU_SOURCE
-
 #include "mkimage.h"
 #include <image.h>
 #include "pblimage.h"
diff --git a/tools/ublimage.c b/tools/ublimage.c
index 6495db6..b4ef7f0 100644
--- a/tools/ublimage.c
+++ b/tools/ublimage.c
@@ -13,9 +13,6 @@
  * SPDX-License-Identifier:	GPL-2.0+ 
  */
 
-/* Required to obtain the getline prototype from stdio.h */
-#define _GNU_SOURCE
-
 #include "mkimage.h"
 #include <image.h>
 #include "ublimage.h"