http://www.mail-archive.com/bug-grep@gnu.org/msg02537.html

diff --git a/src/kwset.c b/src/kwset.c
index 050562e..995be79 100644
--- a/src/kwset.c
+++ b/src/kwset.c
@@ -40,7 +40,7 @@
 #ifdef GREP
 # include "xalloc.h"
 # undef malloc
-# define malloc(s) xmalloc(s)
+# define malloc xmalloc
 #endif

 #define NCHAR (UCHAR_MAX + 1)