* m4/log10f-ieee.m4: New file.
* m4/log10f.m4 (gl_FUNC_LOG10F): If gl_FUNC_LOG10F_IEEE is present,
test whether log10f works with a negative argument. Replace it if not.
* lib/log10f.c (log10f): For negative arguments, return NaN.
* modules/log10f-ieee (Files): Add m4/log10f-ieee.m4.
(configure.ac): Invoke gl_FUNC_LOG10F_IEEE.
* doc/posix-functions/log10f.texi: Mention the log10f-ieee module.
* lib/math.in.h (log10f): Override if REPLACE_LOG10F is 1.
* lib/log10f.c (log10f): If logf exists, use it and provide just the
workaround.
* m4/log10f.m4 (gl_FUNC_LOG10F_WORKS): New macro.
(gl_FUNC_LOG10F): Invoke it. Set REPLACE_LOG10F.
* m4/math_h.m4 (gl_MATH_H_DEFAULTS): Initialize REPLACE_LOG10F.
* modules/math (Makefile.am): Substitute REPLACE_LOG10F.
* modules/log10f (configure.ac): Consider REPLACE_LOG10F.
(Depends-on): Update conditions.
* doc/posix-functions/log10f.texi: Mention the OSF/1 5.1 problem.
* lib/math.in.h (log10f): New declaration.
* lib/log10f.c: New file.
* m4/log10f.m4: New file.
* m4/math_h.m4 (gl_MATH_H): Test whether log10f is declared.
(gl_MATH_H_DEFAULTS): Initialize GNULIB_LOG10F, HAVE_LOG10F.
* modules/math (Makefile.am): Substitute GNULIB_LOG10F, HAVE_LOG10F.
* modules/log10f: New file.
* tests/test-math-c++.cc: Check the declaration of log10f.
* doc/posix-functions/log10f.texi: Mention the new module.