diff --git a/src/include/port/linux.h b/src/include/port/linux.h
index f6aacc67ff..c7d88e396c 100644
--- a/src/include/port/linux.h
+++ b/src/include/port/linux.h
@@ -1,9 +1,3 @@
-/* Force _GNU_SOURCE on; plperl is broken with Perl 5.8.0 otherwise */
-#ifndef _GNU_SOURCE
-#define _GNU_SOURCE 1
-#endif
-
-
 #if defined(__i386__) || defined(__x86_64__)
 typedef unsigned char slock_t;
 
diff --git a/src/template/linux b/src/template/linux
index 0aab11631f..2c4f393e75 100644
--- a/src/template/linux
+++ b/src/template/linux
@@ -1,4 +1,6 @@
 CFLAGS=-O2
+# Force _GNU_SOURCE on; plperl is broken with Perl 5.8.0 otherwise
+CPPFLAGS="-D_GNU_SOURCE"
 
 SUPPORTS_THREADS=yes
 NEED_REENTRANT_FUNCS=yes	# verified glibc 2.1 2003-09-03