Use GLint when getting GL_GENERATE_MIPMAP.

Using GLboolean caused a stack corruption according to VS2012.

src/modules/graphics/opengl/Font.cpp

@@ -496,8 +496,8 @@ void Font::checkMipmapsCreated() const
 	if (!Image::hasMipmapSupport())
 		throw love::Exception("Mipmap filtering is not supported on this system!");
 
-	GLboolean mipmapscreated;
-	glGetTexParameteriv(GL_TEXTURE_2D, GL_GENERATE_MIPMAP, (GLint *)&mipmapscreated);
+	GLint mipmapscreated;
+	glGetTexParameteriv(GL_TEXTURE_2D, GL_GENERATE_MIPMAP, &mipmapscreated);
 
 	// generate mipmaps for this image if we haven't already
 	if (!mipmapscreated)

src/modules/graphics/opengl/Image.cpp

@@ -159,8 +159,8 @@ void Image::checkMipmapsCreated() const
 
 	bind();
 
-	GLboolean mipmapscreated;
-	glGetTexParameteriv(GL_TEXTURE_2D, GL_GENERATE_MIPMAP, (GLint *)&mipmapscreated);
+	GLint mipmapscreated;
+	glGetTexParameteriv(GL_TEXTURE_2D, GL_GENERATE_MIPMAP, &mipmapscreated);
 
 	// generate mipmaps for this image if we haven't already
 	if (!mipmapscreated)