fmod* math error reporting

[Bruno Haible]

The fmod* functions also have portability problems regarding proper IEEE
behaviour:

* fmod
OSF/1 5.1: test-fmod-ieee.h:30: assertion failed
mingw:     test-fmod-ieee.h:48: assertion failed
MSVC 9:    test-fmod-ieee.h:48: assertion failed

* fmodf
OSF/1 5.1: test-fmod-ieee.h:30: assertion failed
MSVC 9:    test-fmod-ieee.h:48: assertion failed

* fmodl
OSF/1 5.1: test-fmod-ieee.h:30: assertion failed
MSVC 9:    test-fmod-ieee.h:48: assertion failed

This series of patches fixes it.


2012-02-27  Bruno Haible  <address@hidden>

        fmodl-ieee: Work around test failures on OSF/1, MSVC 9.
        * m4/fmodl-ieee.m4: New file.
        * m4/fmodl.m4 (gl_FUNC_FMODL): If gl_FUNC_FMODL_IEEE is present, test
        whether fmodl works with zero arguments. Replace it if not.
        * modules/fmodl-ieee (Files): Add m4/fmodl-ieee.m4.
        (Depends-on): Add fmod-ieee.
        (configure.ac): Invoke gl_FUNC_FMODL_IEEE.
        * doc/posix-functions/fmodl.texi: Mention the fmodl-ieee module.

        fmodf-ieee: Work around test failure on OSF/1.
        * m4/fmodf-ieee.m4: New file.
        * m4/fmodf.m4 (gl_FUNC_FMODF): If gl_FUNC_FMODF_IEEE is present, test
        whether fmodf works with zero arguments. Replace it if not.
        * lib/math.in.h (fmodf): Override if REPLACE_FMODF is 1.
        * m4/math_h.m4 (gl_MATH_H_DEFAULTS): Initialize REPLACE_FMODF.
        * modules/math (Makefile.am): Substitute REPLACE_FMODF.
        * modules/fmodf (configure.ac): Consider REPLACE_FMODF.
        (Depends-on): Update dependencies.
        * modules/fmodf-ieee (Files): Add m4/fmodf-ieee.m4.
        (configure.ac): Invoke gl_FUNC_FMODF_IEEE.
        * doc/posix-functions/fmodf.texi: Mention the problem on OSF/1.

        fmodf-ieee: Work around test failure on MSVC 9.
        * modules/fmodf-ieee (Depends-on): Add fmod-ieee.
        * doc/posix-functions/fmodf.texi: Mention the fmodf-ieee module.

        fmod-ieee: Work around test failures on OSF/1, mingw.
        * m4/fmod-ieee.m4: New file.
        * m4/fmod.m4 (gl_FUNC_FMOD): If gl_FUNC_FMOD_IEEE is present, test
        whether fmod works with zero arguments. Replace it if not.
        * lib/math.in.h (fmod): New declaration.
        * lib/fmod.c: New file.
        * m4/math_h.m4 (gl_MATH_H): Test whether fmod is declared.
        (gl_MATH_H_DEFAULTS): Initialize GNULIB_FMOD, REPLACE_FMOD.
        * modules/math (Makefile.am): Substitute GNULIB_FMOD, REPLACE_FMOD.
        * modules/fmod (Files): Add lib/fmod.c.
        (Depends-on): Add math, isinf, trunc, fma.
        (configure.ac): Arrange to compile lib/fmod.c if needed.
        * modules/fmod-ieee (Files): Add m4/fmod-ieee.m4, m4/minus-zero.m4,
        m4/signbit.m4.
        (configure.ac): Invoke gl_FUNC_FMOD_IEEE.
        * tests/test-math-c++.cc: Check the declaration of fmod.
        * doc/posix-functions/fmod.texi: Mention the fmod-ieee module.