Include strings.h which is needed for strcasemp. Some systems declare them

in string.h, but it should be possible to include both.

shared/configfile.c

@@ -15,6 +15,7 @@
 
 #include <stdio.h>
 #include <string.h>
+#include <strings.h>
 #include <unistd.h>
 #include <stdlib.h>