* m4/mkstemp.m4: Remove.
* lib/mkstemp.c: Remove.
* lib/mkostemp.c: New file.
* m4/mkostemp.m4: New file.
* lib/Makefile.am:
* m4/gnulib-cache.m4:
* m4/gnulib-comp.m4: Remove mkstemp module, replace with mkostemp.
* libguile/fports.h:
* libguile/fports.c (scm_i_mode_to_open_flags): Factor out helper to
parse mode string to open flags.
(scm_open_file_with_encoding): Use the new helper.
* libguile/filesys.c:
(scm_i_mkstemp): Adapt to take optional second argument, being a mode
string. Use mkostemp.
(scm_mkstemp): Backwards compatible shim that calls scm_i_mkstemp.
* doc/ref/posix.texi:
* NEWS: Update.
* module/system/base/compile.scm (call-with-output-file/atomic): Pass
"wb" as mode, to cause O_BINARY to be added on MinGW.
