Add support for Android 2.3+

There have been plenty of ppl involved in creating this version.
I don't wanna mention names as I'm sure I'd forget someone so I
just tell where help has been done:
- The partial android versions done by various ppl
- Testing on different android devices
- reviewing code (especially the in core changes)
- testing controls
- reviewing texts

A big thank you to everyone helping this to be completed!

src/config.h

@@ -8,7 +8,10 @@
 
 #define PROJECT_NAME "Minetest"
 #define RUN_IN_PLACE 0
+#define STATIC_SHAREDIR ""
+
 #define USE_GETTEXT 0
+
 #ifndef USE_SOUND
 	#define USE_SOUND 0
 #endif
@@ -17,8 +20,9 @@
 	#define USE_CURL 0
 #endif
 
-#define USE_FREETYPE 0
-#define STATIC_SHAREDIR ""
+#ifndef USE_FREETYPE
+	#define USE_FREETYPE 0
+#endif
 
 #ifndef USE_LEVELDB
 	#define USE_LEVELDB 0
@@ -70,5 +74,11 @@
 	#define VERSION_EXTRA_STRING CMAKE_VERSION_EXTRA_STRING
 #endif
 
+#ifdef __ANDROID__
+	#include "android_version.h"
+#else
+	#include "cmake_config_githash.h"
+#endif
+
 #endif