RGMP 4.0 update from Qiang Yu

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@5305 42af7a65-404d-4744-a932-0658087f49c3

lib/string/lib_strchr.c

@@ -59,6 +59,7 @@
  *
  ****************************************************************************/
 
+#ifndef CONFIG_ARCH_STRCHR
 FAR char *strchr(FAR const char *s, int c)
 {
   if (s)
@@ -74,3 +75,4 @@ FAR char *strchr(FAR const char *s, int c)
 
   return NULL;
 }
+#endif