Make sure strcasecmp() is declared.

On recent glibc versions strings.h is not included by default, so the compiler
will issue a warning for implicit declaration of strcasecmp().
patch by Diego 'Flameeyes' Pettenò, flameeyes gmail com


git-svn-id: file:///var/local/repositories/ffmpeg/trunk@15531 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

vhook/imlib2.c

@@ -53,6 +53,7 @@
 #include <fcntl.h>
 #include <stdarg.h>
 #include <string.h>
+#include <strings.h>
 #include <unistd.h>
 #undef time
 #include <sys/time.h>