Adds support for Android.

This has been tested with both OpenGL and OpenGL ES on Android.
We can't use dlsym on Android to get all the function pointers since Android's libGLES* libraries are just shim libraries that pass everything through
to the real vendor specific libraries.

Due to this we must grab function pointers entirely through eglGetProcAddress instead of dlsym.

src/dispatch_common.c

@@ -104,10 +104,22 @@
 
 #ifdef __APPLE__
 #define GLX_LIB "/opt/X11/lib/libGL.1.dylib"
+#elif defined(ANDROID)
+#define GLX_LIB "libGLESv2.so"
 #else
 #define GLX_LIB "libGL.so.1"
 #endif
 
+#ifdef ANDROID
+#define EGL_LIB "libEGL.so"
+#define GLES1_LIB "libGLESv1_CM.so"
+#define GLES2_LIB "libGLESv2.so"
+#else
+#define EGL_LIB "libEGL.so.1"
+#define GLES1_LIB "libGLESv1_CM.so.1"
+#define GLES2_LIB "libGLESv2.so.2"
+#endif
+
 struct api {
 #ifndef _WIN32
     /**
@@ -380,7 +392,7 @@ epoxy_current_context_is_glx(void)
         return true;
 
 #if PLATFORM_HAS_EGL
-    sym = do_dlsym(&api.egl_handle, "libEGL.so.1", "eglGetCurrentContext",
+    sym = do_dlsym(&api.egl_handle, EGL_LIB, "eglGetCurrentContext",
                    false);
     if (sym && epoxy_egl_get_current_gl_context_api() != EGL_NONE)
         return false;
@@ -416,7 +428,7 @@ epoxy_conservative_has_gl_extension(const char *ext)
 void *
 epoxy_egl_dlsym(const char *name)
 {
-    return do_dlsym(&api.egl_handle, "libEGL.so.1", name, true);
+    return do_dlsym(&api.egl_handle, EGL_LIB, name, true);
 }
 
 void *
@@ -446,7 +458,7 @@ epoxy_gles1_dlsym(const char *name)
     if (epoxy_current_context_is_glx()) {
         return epoxy_get_proc_address(name);
     } else {
-        return do_dlsym(&api.gles1_handle, "libGLESv1_CM.so.1", name, true);
+        return do_dlsym(&api.gles1_handle, GLES1_LIB, name, true);
     }
 }
 
@@ -456,7 +468,7 @@ epoxy_gles2_dlsym(const char *name)
     if (epoxy_current_context_is_glx()) {
         return epoxy_get_proc_address(name);
     } else {
-        return do_dlsym(&api.gles2_handle, "libGLESv2.so.2", name, true);
+        return do_dlsym(&api.gles2_handle, GLES2_LIB, name, true);
     }
 }
 
@@ -476,7 +488,7 @@ epoxy_gles3_dlsym(const char *name)
     if (epoxy_current_context_is_glx()) {
         return epoxy_get_proc_address(name);
     } else {
-        void *func = do_dlsym(&api.gles2_handle, "libGLESv2.so.2", name, false);
+        void *func = do_dlsym(&api.gles2_handle, GLES2_LIB, name, false);
 
         if (func)
             return func;
@@ -494,6 +506,12 @@ epoxy_get_core_proc_address(const char *name, int core_version)
 {
 #ifdef _WIN32
     int core_symbol_support = 10;
+#elif defined(ANDROID)
+    /**
+     * All symbols must be resolved through eglGetProcAddress
+     * on Android
+     */
+    int core_symbol_support = 0;
 #else
     int core_symbol_support = 12;
 #endif
@@ -564,7 +582,7 @@ epoxy_get_bootstrap_proc_address(const char *name)
      * non-X11 ES2 context from loading a bunch of X11 junk).
      */
 #if PLATFORM_HAS_EGL
-    get_dlopen_handle(&api.egl_handle, "libEGL.so.1", false);
+    get_dlopen_handle(&api.egl_handle, EGL_LIB, false);
     if (api.egl_handle) {
         switch (epoxy_egl_get_current_gl_context_api()) {
         case EGL_OPENGL_API:
@@ -575,7 +593,7 @@ epoxy_get_bootstrap_proc_address(const char *name)
              * us.  Try the GLES2 implementation first, and fall back
              * to GLES1 otherwise.
              */
-            get_dlopen_handle(&api.gles2_handle, "libGLESv2.so.2", false);
+            get_dlopen_handle(&api.gles2_handle, GLES2_LIB, false);
             if (api.gles2_handle)
                 return epoxy_gles2_dlsym(name);
             else

src/dispatch_common.h

@@ -33,6 +33,11 @@
 #define PLATFORM_HAS_GLX 1
 #define PLATFORM_HAS_WGL 0
 #define EPOXY_IMPORTEXPORT
+#elif defined(ANDROID)
+#define PLATFORM_HAS_EGL 1
+#define PLATFORM_HAS_GLX 0
+#define PLATFORM_HAS_WGL 0
+#define EPOXY_IMPORTEXPORT
 #else
 #define PLATFORM_HAS_EGL 1
 #define PLATFORM_HAS_GLX 1