And here's the rationale for this patch:
Compiling a testdir of fenv-exceptions-trapping with a cross-compiler
(CC=riscv64-linux-gnu-gcc ./configure --host=riscv64-linux-gnu), I get a
compilation error:
../../gltests/test-fenv-except-trapping-2.c: In function 'raise_invalid_snan':
../../gltests/test-fenv-except-trapping-2.c:193:13: warning: implicit
declaration of function 'SNaNl'; did you mean 'SNaNd'?
[-Wimplicit-function-declaration]
193 | a = SNaNl (); b = 1.0L;
| ^~~~~
| SNaNd
The cause is that LDBL_EXPBIT0_WORD and LDBL_EXPBIT0_BIT were not determined
at configure-time.
This patch fixes it.
