checkpolicy: Android/MacOS X build support

Android/MacOS X build support for checkpolicy.
Create a Android.mk file for Android build integration.
Introduce DARWIN ifdefs for building on MacOS X.

Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Dan Walsh <dwalsh@redhat.com>
diff --git a/checkpolicy/checkpolicy.c b/checkpolicy/checkpolicy.c
index a35a749..544f235 100644
--- a/checkpolicy/checkpolicy.c
+++ b/checkpolicy/checkpolicy.c
@@ -70,6 +70,10 @@
 #include <errno.h>
 #include <sys/mman.h>
 
+#ifdef DARWIN
+#include <ctype.h>
+#endif
+
 #include <sepol/policydb/policydb.h>
 #include <sepol/policydb/services.h>
 #include <sepol/policydb/conditional.h>