* MODULES.html.sh: Document tempname.

* MODULES.html.sh: Document tempname.
* modules/mkstemp (Depends-on): Add tempname, and drop transitive
dependencies.
(Files): Move lib/tempname.c...
* modules/tempname: ...to this new module.
* m4/mkstemp.m4 (gl_FUNC_MKSTEMP): Remove tempname checks.
(gl_PREREQ_TEMPNAME): Move...
* m4/tempname.m4: ...to this new file.
* lib/mkstemp.c (includes) [!_LIBC]: Use tempname.h.
* modules/sys_stat (Depends-on): Add stat-macros.
* lib/stat_.h (includes): Pick up stat macros.
* m4/sys_stat_h.m4 (gl_HEADER_SYS_STAT_H): Replace <sys/stat.h>
if stat macros are broken.
* lib/tempname.c (includes): No need to include "stat-macros.h".
(__gen_tempname) [!_LIBC]: Expose as gen_tempname.
(direxists, __path_search) [!_LIBC]: Don't compile these in
gnulib; the tmpdir module covers that.
* lib/tempname.h: New file.