libusb: Configuration logfiles contain indications of -Wimplicit-function-declaration in "strchr"

[judaew (Vadym-Valdis Yudaiev)]

--->  Configuring libusb
Warning: Configuration logfiles contain indications of -Wimplicit-function-declaration; check that features were not accidentally disabled:
  strchr: found in libusb-libusb-4622bfc/config.log

See #64590 and WimplicitFunctionDeclaration.

[michaelld (Michael Dickens)]

Getting such an error may be intentional by the developer. In this case this is an intentional check to see if strchr is implicitly defined or not. The code is actually part of autoconf, not libusb. I have a patch to add a #warning to this test in AC; with this patch, we could tweak then Wimplicit-function-declaration port check for the warning to not report these specific messages (which I don't have a patch for yet). Beyond this patch, I'm not aware of a way of hiding theses messages.

[jmroot (Joshua Root)]

You can add strchr to configure.checks.implicit_function_declaration.whitelist, but it's kind of a pain do to that for all ports that configure with autoconf >= 2.70 (and there's the perhaps unlikely but real possibility that this might hide a real problem with use of strchr in future).

[jmroot (Joshua Root)]

Ugh sorry, Trac reverted some of your changes without being asked.

[ryandesign (Ryan Carsten Schmidt)]

configure.checks.implicit_function_declaration.whitelist-append strchr is indeed what I have been adding to ports in this situation.

[michaelld (Michael Dickens)]

In 83668d4a28d51fb72c01fb40db7d76d5bf4a5605/macports-ports (master):

libusb: ignore strchr implicit function test

This test is actually part of autoconf, and is intentional. Hence, ignore it here.

Closes: #64602

[judaew (Vadym-Valdis Yudaiev)]

Thanks Michael and Joshua!