Fixed compiler warning.

main/php_scandir.c

@@ -40,6 +40,8 @@
 #endif
 
 #ifndef HAVE_ALPHASORT
+ #include <string.h>
+
 int alphasort(const struct dirent **a, const struct dirent **b)
 {
 	return strcoll((*a)->d_name,(*b)->d_name);