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/runtests

@@ -54,6 +54,16 @@ while read t; do
   esac
 done < test-spirv-list
 
+#
+# Preprocessor tests
+#
+while read t; do
+    echo Running Preprocessor $t...
+    b=`basename $t`
+    $EXE -E $t > $TARGETDIR/$b.out
+    diff -b $BASEDIR/$b.out $TARGETDIR/$b.out || HASERROR=1
+done < test-preprocessor-list
+
 #
 # grouped shaders for bulk (faster) tests
 #