[PATCH] Don't use TEST_CXX as CXX for build

[Joseph Myers]

On Sun, 15 Dec 2024, Sam James wrote:

> Looks like
> https://inbox.sourceware.org/libc-testresults/173422834592.2674304.8851778744134595286@tor.usersys.redhat.com/
> failed again which is probably related to this.

ColdFire GCC build failures are GCC bug 116244 (and 103370 for assembler 
errors building glibc which have gone away and come back a few times), 
nothing to do with this change, and should not be confused with failures 
building the testsuite.

-- 
Joseph S. Myers
josmyers@redhat.com