Add this script to Build Phases of your target in Xcode to automatically set build number with SVN/Git revision number

revision.sh

# set build number only for release (Product|Archive)
if [ "$CONFIGURATION" == "Release" ]; then
	
	# get GIT revision number
	buildNumber=`git rev-list --count HEAD`

	# if not git, then get SVN revision  number
	if [[ -z "$buildNumber" ]]; then 
		buildNumber=`svn info | grep "Revision" | awk '{print $2}'`
	fi

	# set default value if no rev number found
	if [[ -z "$buildNumber" ]]; then buildNumber=1; fi

	# write build number into project plit file
	/usr/libexec/PlistBuddy -c "Set :CFBundleVersion ${buildNumber}" "${INFOPLIST_FILE}"
fi