* m4/check-math-lib.m4 (gl_CHECK_MATH_LIB): Accept an optional third
argument.
* m4/round.m4 (gl_FUNC_ROUND): Search for round() in the libraries
also when it is not declared. Set HAVE_ROUND. For replacement code,
test HAVE_ROUND, not HAVE_DECL_ROUND.
* modules/round (configure.ac): For replacement code, test HAVE_ROUND,
not HAVE_DECL_ROUND.
(Depends-on): Update conditions.
* modules/round-ieee (Depends-on): Update conditions.
* doc/posix-functions/round.texi: Mention the IRIX problem.
* modules/round-ieee (Depends-on): Add floor-ieee, ceil-ieee.
* doc/posix-functions/round.texi: Mention problem with negative
arguments.
* doc/posix-functions/ceil.texi: Mention problem on OSF/1 5.1.
* modules/round-ieee: New file.
* m4/round.m4 (gl_FUNC_ROUND): If gl_FUNC_ROUND_IEEE is also used, test
whether round works according to ISO C 99 with IEC 60559.
* m4/round-ieee.m4: New file.
* modules/round-ieee-tests: New file.
* tests/test-round-ieee.c: New file, based on tests/test-roundf-ieee.c.
* tests/test-round1.c (main): Remove signbit tests.
* modules/round-tests (Depends-on): Remove 'signbit'.
* doc/posix-functions/round.texi: Mention the new module.
