Move -D_GNU_SOURCE hack from port header to template, so that

tglsfdc · tglsfdc · commit 026f9c05d5eb · 2003-09-26T17:39:13.000Z
configure's tests see the same compilation environment as the code.
Per discussion with Stephan Szabo.
diff --git 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
@@ -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
