configure sets GCC=yes for clang

Tomas Vondra <tomas.vondra@enterprisedb.com> writes:

I've been doing some experiments with compilers, and I've noticed that
when using clang configure still ends up setting
GCC='yes'
which seems somewhat strange.

I'm pretty sure that's intentional. clang tries to be a gcc-alike,
and mostly succeeds, other than variations in command line options.
It's better to set GCC=yes and deal with the small discrepancies
than not set it and have to deal with clang as a whole separate case.

FWIW I've noticed because when building
with "-Ofast" (yeah, I'm just playing with stuff) it fails like this:

checking whether the C compiler still works... yes
configure: error: do not put -ffast-math in CFLAGS

which is in $GCC=yes check, and clang doesn't even have such option.

Well, the error is correct, even if clang doesn't spell the switch the
same way: you enabled fast-math optimizations and we don't want that.

[ wanders away wondering how meson handles this stuff ... ]

regards, tom lane