diff --git a/arch/aarch64/makecontext.c b/arch/aarch64/makecontext.c
index 5afd0ac..e79ac7f 100644
--- a/arch/aarch64/makecontext.c
+++ b/arch/aarch64/makecontext.c
@@ -10,7 +10,9 @@
  * from the use of this software.
  */
 
+#ifndef _GNU_SOURCE
 #define _GNU_SOURCE
+#endif
 #include <stddef.h>
 #include <stdarg.h>
 #include <string.h>
diff --git a/arch/arm/makecontext.c b/arch/arm/makecontext.c
index 76191fa..fd46df1 100644
--- a/arch/arm/makecontext.c
+++ b/arch/arm/makecontext.c
@@ -10,7 +10,9 @@
  * from the use of this software.
  */
 
+#ifndef _GNU_SOURCE
 #define _GNU_SOURCE
+#endif
 #include <stddef.h>
 #include <stdarg.h>
 #include <string.h>
diff --git a/arch/m68k/makecontext.c b/arch/m68k/makecontext.c
index f567eb2..fb380f1 100644
--- a/arch/m68k/makecontext.c
+++ b/arch/m68k/makecontext.c
@@ -10,7 +10,9 @@
  * from the use of this software.
  */
 
+#ifndef _GNU_SOURCE
 #define _GNU_SOURCE
+#endif
 #include <stddef.h>
 #include <stdarg.h>
 #include <string.h>
diff --git a/arch/ppc/makecontext.c b/arch/ppc/makecontext.c
index a91104e..f8ed384 100644
--- a/arch/ppc/makecontext.c
+++ b/arch/ppc/makecontext.c
@@ -11,7 +11,9 @@
  * from the use of this software.
  */
 
+#ifndef _GNU_SOURCE
 #define _GNU_SOURCE
+#endif
 #include <stdarg.h>
 #include <stdint.h>
 
diff --git a/arch/ppc64/makecontext.c b/arch/ppc64/makecontext.c
index aafccec..e42d66a 100644
--- a/arch/ppc64/makecontext.c
+++ b/arch/ppc64/makecontext.c
@@ -11,7 +11,9 @@
  * from the use of this software.
  */
 
+#ifndef _GNU_SOURCE
 #define _GNU_SOURCE
+#endif
 #include <stdarg.h>
 #include <stdint.h>
 
diff --git a/arch/riscv64/makecontext.c b/arch/riscv64/makecontext.c
index a456d5c..aee671c 100644
--- a/arch/riscv64/makecontext.c
+++ b/arch/riscv64/makecontext.c
@@ -10,7 +10,9 @@
  * from the use of this software.
  */
 
+#ifndef _GNU_SOURCE
 #define _GNU_SOURCE
+#endif
 #include <stddef.h>
 #include <stdarg.h>
 #include <string.h>
diff --git a/arch/s390x/makecontext.c b/arch/s390x/makecontext.c
index 6f7cc8e..f970da4 100644
--- a/arch/s390x/makecontext.c
+++ b/arch/s390x/makecontext.c
@@ -10,7 +10,9 @@
  * from the use of this software.
  */
 
+#ifndef _GNU_SOURCE
 #define _GNU_SOURCE
+#endif
 #include <stddef.h>
 #include <stdarg.h>
 #include <string.h>
diff --git a/arch/sh/makecontext.c b/arch/sh/makecontext.c
index b039dfd..9bc4782 100644
--- a/arch/sh/makecontext.c
+++ b/arch/sh/makecontext.c
@@ -10,7 +10,9 @@
  * from the use of this software.
  */
 
+#ifndef _GNU_SOURCE
 #define _GNU_SOURCE
+#endif
 #include <stddef.h>
 #include <stdarg.h>
 #include <string.h>
diff --git a/arch/x86/makecontext.c b/arch/x86/makecontext.c
index 571c13b..8d7fbf5 100644
--- a/arch/x86/makecontext.c
+++ b/arch/x86/makecontext.c
@@ -11,7 +11,9 @@
  * from the use of this software.
  */
 
+#ifndef _GNU_SOURCE
 #define _GNU_SOURCE
+#endif
 #include <stddef.h>
 #include <stdarg.h>
 #include <string.h>
diff --git a/arch/x86_64/makecontext.c b/arch/x86_64/makecontext.c
index 4458507..836ca62 100644
--- a/arch/x86_64/makecontext.c
+++ b/arch/x86_64/makecontext.c
@@ -10,7 +10,9 @@
  * from the use of this software.
  */
 
+#ifndef _GNU_SOURCE
 #define _GNU_SOURCE
+#endif
 #include <stddef.h>
 #include <stdarg.h>
 #include <string.h>