Include <ctype.h> for use of isalpha.

diff --git a/m4/strerror_r.m4 b/m4/strerror_r.m4
index 1e57f27..72c7551 100644 (file)
--- a/m4/strerror_r.m4
+++ b/m4/strerror_r.m4
@@ -42,6 +42,7 @@ if test $ac_cv_func_strerror_r = yes; then
        [
 #       include <stdio.h>
 #       include <string.h>
+#       include <ctype.h>
 
        extern char *strerror_r ();