Strings must contain ONLY numbers to be integers

The old pattern matched if there was an integer (digit) in the string;
it would have to be all non-digits to be quoted.
Create a version string including source code hash

This code combines the specified version number (the logical release
target) with the actual source code has, to identify which version the
build was from.

Put ${project}_VERSION_STRING into ${project}_CONFIG_VARS to get this
into your code (e.g. to print as a version string).
Include version string from project files into code
Merge pull request #17 from rolk/017_gitsha

Embed a version string into the project