Re: Regression: git no longer works with musl libc's regex impl

On Thu, Oct 06, 2016 at 09:18:29PM +0200, Ævar Arnfjörð Bjarmason wrote:

On Tue, Oct 4, 2016 at 6:08 PM, Johannes Schindelin
[off-list ref] wrote:

quoted

As to making NO_REGEX conditional on REG_STARTEND: you are talking about
apples and oranges here. NO_REGEX is a Makefile flag, while REG_STARTEND
is a C preprocessor macro.

Unless you can convince the rest of the Git developers (you would not
convince me) to simulate autoconf by compiling an executable every time
`make` is run, to determine whether REG_STARTEND is defined, this is a
no-go.

But just to clarify, does anyone have any objection to making our
configure.ac compile a C program to check for this sort of thing?
Because that seems like the easiest solution to this class of problem.

No, I think that is the exact purpose of configure.ac and autoconf.

It would be neat if we could auto-fallback during the build. Rich
suggested always compiling compat/regex.c, and just having it be a noop
at the preprocessor level. I'm not sure if that would work, though,
because we'd have to include the system "regex.h" to know if we have
REG_STARTEND, at which point it is potentially too late to compile our
own regex routines (we're potentially going to conflict with the system
declarations).

-Peff