PA_GIT_REVISION: new scripts to replace SVN revision

update_gitrevision.sh should be run before building on Mac or Linux.

update_gitrevision.sh

@@ -0,0 +1,17 @@
+#!/bin/bash
+#
+# Write the Git commit SHA to an include file.
+# This should be run before compiling code on Linux or Macintosh.
+#
+revision_filename=src/common/pa_gitrevision.h
+
+# Run git first to make sure it is installed before corrupting the
+# include file.
+git rev-parse HEAD
+
+# Update the include file with the current Git revision.
+echo -n "#define PA_GIT_REVISION " > ${revision_filename}
+git rev-parse HEAD >> ${revision_filename}
+
+echo ${revision_filename} now contains
+cat ${revision_filename}