New module 'fmodl'. * lib/math.in.h (fmodl): New declaration. * lib/fmodl.c: New file. * m4/fmodl.m4: New file. * m4/math_h.m4 (gl_MATH_H): Test whether fmodl is declared. (gl_MATH_H_DEFAULTS): Initialize GNULIB_FMODL, HAVE_FMODL, REPLACE_FMODL. * modules/math (Makefile.am): Substitute GNULIB_FMODL, HAVE_FMODL, REPLACE_FMODL. * modules/fmodl: New file. * doc/posix-functions/fmodl.texi: Mention the new module.