fmod* tests: More tests.

fmod* tests: More tests.

* tests/test-fmod.h: New file.
* tests/test-fmod.c: Include <float.h> and test-fmod.h.
(main): Invoke test_function.
* tests/test-fmodf.c: Include <float.h> and test-fmod.h.
(main): Invoke test_function.
* tests/test-fmodl.c: Include <float.h> and test-fmod.h.
(main): Invoke test_function.
* modules/fmod-tests (Files): Add tests/test-fmod.h, tests/randomd.c.
(Makefile.am): Add randomd.c to test_fmod_SOURCES.
* modules/fmodf-tests (Files): Add tests/test-fmod.h, tests/randomf.c.
(Makefile.am): Add randomf.c to test_fmodf_SOURCES.
* modules/fmodl-tests (Files): Add tests/test-fmod.h, tests/randoml.c.
(Depends-on): Add 'float'.
(Makefile.am): Add randoml.c to test_fmodl_SOURCES.