Add support for ARB_uniform_buffer_object

GLSL Version : >= 120

Purpose:
Allow users to use features by enabling this extension, even in low versions.

Extension Name:
ARB_uniform_buffer_object

Builtin-variables:
Uniform

Builtin-functions:
Nah

Keywords:
Nah

Features:
uniform block

Reference:
https://www.khronos.org/registry/OpenGL/extensions/ARB/ARB_uniform_buffer_object.txt

Test/120.vert

@@ -201,3 +201,15 @@ int mac;
 
 #define macr(A,B) A ## B
 int macr(qrs,tuv);
+
+layout(std140) uniform BlockName    // ERROR
+{
+    int test;
+};
+
+#extension GL_ARB_uniform_buffer_object : enable
+
+layout(std140) uniform BlockName
+{
+    int test;
+};