--- GNUmakefile.in
+++ GNUmakefile.in
@@ -282,7 +282,7 @@
 # Add your flags here
 OTHER_CFLAGS =
 
-CFLAGS = @CFLAGS@ @CPPFLAGS@ $(OTHER_CFLAGS) $(SPECIAL_CFLAGS) -Wall
+CFLAGS = @CFLAGS@ @CPPFLAGS@ -D_GNU_SOURCE $(OTHER_CFLAGS) $(SPECIAL_CFLAGS) -Wall
 
 LDFLAGS = @LDFLAGS@ $(DEBUG_CFLAGS) $(SPECIAL_CFLAGS)
 
--- parsers.c
+++ parsers.c
@@ -44,12 +44,6 @@
 #include <assert.h>
 #include <string.h>
 
-#ifdef __GLIBC__
-/*
- * Convince GNU's libc to provide a strptime prototype.
- */
-#define __USE_XOPEN
-#endif /*__GLIBC__ */
 #include <time.h>
 
 #ifdef FEATURE_ZLIB