Set shader again after displaying OSD

Some titles like Resident Evil 2/Biohazard 2 display a cutscene and the shader
is only set for the first frame. The next frames just expect that the old
shader is still set.

The OSD workaround only disabled the shader program before and expected that
the next frame automatically sets it again. This assumption was wrong and
instead the program has to be reassigned again to the current rendering
context when the renderCallback for the OSD was called.

src/Glitch64/glitchmain.cpp

@@ -1661,11 +1661,17 @@ grBufferClear( GrColor_t color, GrAlpha_t alpha, FxU32 depth )
 FX_ENTRY void FX_CALL
 grBufferSwap( FxU32 swap_interval )
 {
+   GLuint program;
+
 	glFinish();
-  glUseProgramObjectARB(0);
 //  printf("rendercallback is %p\n", renderCallback);
-  if(renderCallback)
+  if(renderCallback) {
+      glGetIntegerv(GL_CURRENT_PROGRAM, (GLint*) &program);
+      glUseProgramObjectARB(0);
       (*renderCallback)(1);
+      if (program)
+         glUseProgramObjectARB(program);
+  }
   int i;
   LOG("grBufferSwap(%d)\r\n", swap_interval);
   //printf("swap\n");