Added support for data directory on Android.

This makes GNUstep use the path returned by Context.getFilesDir() as the basis for storing data (e.g. NSUserDefaults) and when querying system directory paths (NSLibraryDirectory, NSApplicationSupportDirectory, etc.). Requires calling a new GSInitializeProcessAndroid() initialization function.

Headers/Foundation/NSProcessInfo.h

@@ -30,6 +30,10 @@
 
 #import	<Foundation/NSObject.h>
 
+#ifdef __ANDROID__
+#include <jni.h>
+#endif
+
 #if	defined(__cplusplus)
 extern "C" {
 #endif
@@ -265,6 +269,12 @@ DEFINE_BLOCK_TYPE(GSPerformExpiringActivityBlock, void, BOOL);
 + (void) initializeWithArguments: (char**)argv
                            count: (int)argc
                      environment: (char**)env;
+
+#ifdef __ANDROID__
+- (jobject) androidContext;
+- (NSString *) androidFilesDir;
+#endif
+
 @end
 
 /**
@@ -278,6 +288,16 @@ DEFINE_BLOCK_TYPE(GSPerformExpiringActivityBlock, void, BOOL);
  */
 GS_EXPORT void GSInitializeProcess(int argc, char **argv, char **envp);
 
+#ifdef __ANDROID__
+/**
+ * Android process initialization function.
+ * This should be called on Android to initialize GNUstep with the JNI
+ * environment and application context, which is used to set up support
+ * for the Android data directory and asset loading via NSBundle.
+ */
+GS_EXPORT void GSInitializeProcessAndroid(JNIEnv *env, jobject context);
+#endif
+
 /**
  * Function for rapid testing to see if a debug level is set.<br />
  * This is used by the debugging macros.<br />