glutil: add glaGetOneInt helper

source/blender/editors/include/BIF_glutil.h

@@ -94,6 +94,7 @@ void glutil_draw_filled_arc(float start, float angle, float radius, int nsegment
  * The param must cause only one value to be gotten from GL.
  */
 float glaGetOneFloat(int param);
+int glaGetOneInt(int param);
 
 /**
  * Functions like glRasterPos2i, except ensures that the resulting

source/blender/editors/screen/glutil.c

@@ -327,6 +327,13 @@ float glaGetOneFloat(int param)
 	return v;
 }
 
+int glaGetOneInt(int param)
+{
+	GLint v;
+	glGetIntegerv(param, &v);
+	return v;
+}
+
 void glaRasterPosSafe2f(float x, float y, float known_good_x, float known_good_y)
 {
 	GLubyte dummy = 0;