Build fixes for Android including platform macro & missing mblen()

src/core/charutil.cpp

@@ -41,6 +41,13 @@
 #include "charutil.h"
 #include "ntmbs.h"
 
+#if IS_ANDROID
+int mblen(const char *s, size_t n)
+{
+  return mbtowc(0, s, n);
+}
+#endif
+
 //  
 // finds the next whole character in string identified by ['cur'-'end')
 // identifies beginning of char in 'first', then end of character in 'last'

src/core/platform.h

@@ -123,7 +123,7 @@
 	#define IS_DOS_DJGPP        1
 	
 	
-#elif defined(__ANDROID_API__)
+#elif defined(__ANDROID__)
     #define OS					OS_ANDROID
 	#define IS_ANDROID          1