xgl: Update to specific version of external libraries

As the BIL spec is rapidly changing, we will explicitly
check out the working version at the time the driver
was tested. Need to update the REVISION values in
the update_external_sources.sh to update to later versions
of BIL.
diff --git a/update_external_sources.sh b/update_external_sources.sh
index 9beb7b9..388c488 100755
--- a/update_external_sources.sh
+++ b/update_external_sources.sh
@@ -2,6 +2,10 @@
 # Update source for glslang and LLVM
 # Copy necessary BIL pieces into glslang and LLVM
 
+BIL_REVISION=28725
+LUNARGLASS_REVISION=1052
+GLSLANG_REVISION=28653
+
 BUILDDIR=$PWD
 BASEDIR=$BUILDDIR/..
 
@@ -15,7 +19,7 @@
 function update_glslang () {
    echo "Updating $BASEDIR/glslang"
    cd $BASEDIR/glslang
-   svn update
+   svn update -r "$GLSLANG_REVISION"
 }
 
 function create_LunarGLASS () {
@@ -44,14 +48,14 @@
 function update_LunarGLASS () {
    echo "Updating $BASEDIR/LunarGLASS"
    cd $BASEDIR/LunarGLASS
-   svn update
+   svn update -r "$LUNARGLASS_REVISION"
 }
 
 function update_BIL () {
    if [ -d "$BASEDIR/BIL" ]; then
      # Update source
      cd $BASEDIR/BIL
-     svn update
+     svn update -r "$BIL_REVISION"
      # copy of necessary BIL pieces into glslang
      cp $BASEDIR/BIL/glslangOverlay_into_BIL/* $BASEDIR/glslang/BIL
      cp $BASEDIR/BIL/Bil.h $BASEDIR/glslang/BIL
@@ -108,5 +112,5 @@
 update_LunarGLASS
 update_BIL
 
-build_LunarGLASS
 build_glslang
+build_LunarGLASS