internal/glimpl: hook up glTexStorage2D on iOS

The glTexStorage2D is part of OpenGL ES 3, but wasn't its function
pointer wasn't initialized on iOS.

Fixes a crash on startup on iOS devices and simulators.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

internal/glimpl/gl_unix.go

@@ -152,6 +152,7 @@ __attribute__((constructor)) static void gio_loadGLFunctions() {
 	_glEndQuery = glEndQuery;
 	_glGenQueries = glGenQueries;
 	_glGetQueryObjectuiv = glGetQueryObjectuiv;
+	_glTexStorage2D = glTexStorage2D;
 	#endif
 	_glBindBufferBase = glBindBufferBase;
 	_glGetUniformBlockIndex = glGetUniformBlockIndex;