Move getline and getdelim into stdio.h, per POSIX 200x.

Move getline and getdelim into stdio.h, per POSIX 200x.
* modules/getline (Files): Remove getline.h.
(Depends-on): Add stdio.
(configure.ac): Add module indicator.
* modules/getdelim (Files): Remove getdelim.h.
(Depends-on): Add stdio.
(configure.ac): Add module indicator.
* modules/stdio (Makefile.am): Work with new indicators.
* m4/stdio_h.m4 (gl_STDIO_H_DEFAULTS): Add new defaults.
* m4/getdelim.m4 (gl_FUNC_GETDELIM): Work with stdio needs.
* m4/getline.m4 (gl_FUNC_GETLINE): Likewise.
* lib/getdelim.h: Delete.
* lib/getline.h: Delete.
* lib/stdio_.h (getdelim, getline): Declare.
* modules/getdelim-tests: New module.
* modules/getline-tests: Likewise.
* tests/test-getdelim.c: New file.
* tests/test-getline.c: Likewise.
* NEWS: Document the change.
* lib/getline.c: Update choice of header.
* lib/csharpcomp.c: Likewise.
* lib/getpass.c: Likewise.
* lib/javacomp.c: Likewise.
* lib/javaversion.c: Likewise.
* lib/yesno.c: Likewise.
* lib/getdelim.c: Likewise.
(getdelim): Set errno on failure, and avoid memory leak.