Perform an operation on each config variable matching a regular expression.
This behaves like git_config_foreach
with an additional filter of a
regular expression that filters which config keys are passed to the
callback.
The regular expression is applied case-sensitively on the normalized form of the variable name: the section and variable parts are lower-cased. The subsection is left unchanged.
The regular expression is applied case-sensitively on the normalized form of the variable name: the case-insensitive parts are lower-case.
regular expression to match against config names
the data to pass to the callback
0 or the return value of the callback which didn't return 0