[PATCH] cleanup: Pull in <string.h> for memchr

This needs further inspection on more systems
---
 lib/compat/strnlen.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/lib/compat/strnlen.c b/lib/compat/strnlen.c
index d02bb4bbd..6a7eb0454 100644
--- a/lib/compat/strnlen.c
+++ b/lib/compat/strnlen.c
@@ -22,6 +22,10 @@
 
 #include "compat.h"
 
+#ifdef HAVE_STRING_H
+# include <string.h>
+#endif
+
 /* Find the length of STRING, but scan at most MAXLEN characters.
    If no '\0' terminator is found in that many characters, return MAXLEN.  */