uCLibc may not have complete fenv.h support even if header present

[aperezdc]

This is related to bug #279971 in WebKit.

I am not 100% sure how things work when building the uClibc C library, but my understanding is that the only a few architectures provide all the functions from fenv.h, and even on architectures where support is partial (or missing) the configuration program will allow setting UCLIBC_HAS_FENV=y regardless.

So it seems that when building against uClibc more smarts than only checking __has_include(<fenv.h>) may be needed.

[mr-c]

Hello @aperezdc and thank you for the report. Is webkit using uClibc or https://uclibc-ng.org/ ? Which version(s)?

[mr-c]

A PR to add a better check would be very welcome, of course

[ThomasDevoogdt]

Hello @aperezdc and thank you for the report. Is webkit using uClibc or https://uclibc-ng.org/ ? Which version(s)?

The uClibc was forked in 2014, see https://uclibc-ng.org/. So I don't think that this one is very relevant. The compile issue was seen by using buildroot which ships with uClibc-ng v1.0.50. See https://github.com/buildroot/buildroot/blob/2024.08.1/package/uclibc/uclibc.mk.