glslang preprocessing: Add -E option to print out preprocessed GLSL, and do the work needed to generate a preprocessed stream. From Andrew Woloszyn <awoloszyn@google.com>.

git-svn-id: https://cvs.khronos.org/svn/repos/ogl/trunk/ecosystem/public/sdk/tools/glslang@31508 e7fa87d3-cd2b-0410-9028-fcbf551c1848

Test/preprocessor.function_macro.vert

@@ -0,0 +1,20 @@
+#version 310 es
+
+
+#define X(n) n + 1
+#define Y(n, z) n + z
+#define Z(f) X(f)
+
+#define REALLY_LONG_MACRO_NAME_WITH_MANY_PARAMETERS(X1, X2, X3, X4, X5, X6, X7,\
+    X8, X9, X10, X11, X12) X1+X2+X3+X4+X5+X6+X7+X8+X9+X10+X11+X12
+
+#define A(\
+  Y\
+  )\
+4 + 3 + Y
+
+int main() {
+  gl_Position = vec4(X(3), Y(3, 4), Z(3));
+  gl_Position = vec4(REALLY_LONG_MACRO_NAME_WITH_MANY_PARAMETERS(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12));
+  gl_Position = vec4(A(3));
+}