xprintf, xprintf-posix, xprintf-gnu: Use *zprintf. * lib/xprintf.h (xprintf, xvprintf, xfprintf, xvfprintf): Change return type to off64_t. Move documentation from xprintf.c to here. Mention EOVERFLOW as another possible error unrelated to file I/O. * lib/xprintf.c (xprintf): Change return type to off64_t. (xvprintf): Likewise. Use vzprintf. (xfprintf): Change return type to off64_t. (xvfprintf): Likewise. Use vfzprintf. * modules/xprintf (Description): Mention also fprintf. Mention EOVERFLOW as another possible error unrelated to file I/O. (Depends-on): Add vzprintf, vfzprintf. * modules/xprintf-posix (Description): Mention also fprintf. Mention EOVERFLOW as another possible error unrelated to file I/O. (Depends-on): Add vzprintf-posix, vfzprintf-posix. Remove vprintf-posix, vfprintf-posix. * modules/xprintf-gnu (Description): Mention also fprintf. Mention EOVERFLOW as another possible error unrelated to file I/O. (Depends-on): Add vzprintf-gnu, vfzprintf-gnu. Remove vprintf-gnu, vfprintf-gnu. * tests/test-xprintf-posix.c (RETTYPE): Change to off64_t. * tests/test-xfprintf-posix.c (RETTYPE): Likewise. * NEWS: Document the change.