* tests/test-floor-ieee.c: Include isnand-nolibm.h, infinity.h, nan.h.
(main): Add tests for [MX] shaded specification in POSIX.
* modules/floor-ieee-tests (Files): Add tests/infinity.h, tests/nan.h.
(Depends-on): Add isnand-nolibm.

* modules/floor-ieee: New file.
* m4/floor.m4 (gl_FUNC_FLOOR): Require gl_MATH_H_DEFAULTS. If
gl_FUNC_FLOOR_IEEE is also used, test whether floor works according to
ISO C 99 with IEC 60559.
* m4/floor-ieee.m4: New file.
* modules/floor (Files): Add lib/floor.c.
(Depends-on): Add 'float'.
(configure.ac): Invoke gl_MATH_MODULE_INDICATOR.
* lib/math.in.h (floor): New declaration.
* m4/math_h.m4 (gl_MATH_H_DEFAULTS): Initialize GNULIB_FLOOR,
REPLACE_FLOOR.
* modules/math (Makefile.am): Substitute GNULIB_FLOOR, REPLACE_FLOOR.
* modules/floor-ieee-tests: New file.
* tests/test-floor-ieee.c: New file, based on tests/test-floorf-ieee.c.
* tests/test-math-c++.cc: Check the signature of 'floor'.
* doc/posix-functions/floor.texi: Mention the new module.