fix the HAVE_GETCWD_NULL code to behave more like the
!HAVE_GETCWD_NULL code used to.
Include "xalloc.h".
(xgetcwd): Do not return NULL when memory is exhausted; instead,
invoke xalloc_die.
Use ssize_t, not int, to store result of readlink.
Check for ssize_t overflow as well as size_t overflow,
as POSIX says the result of readlink is implementation-defined
when ssize_t overflows.
Remove unnecessary cast to char*.
Use free+malloc instead of realloc, as the storage doesn't need
to be preserved and it's clearer and can be more efficient that way.
(SIZE_MAX, SSIZE_MAX): New macros, if <limits.h> doesn't declare.
like the HAVE_GETCWD_NULL code.
Include pathmax.h if not HAVE_GETCWD.
Do not include xalloc.h.
(INITIAL_BUFFER_SIZE): New symbol.
Do not use xmalloc / xrealloc, since the caller is responsible for
handling errors. Preserve errno around `free' during failure.
Do not overrun buffer when using getwd.
Include stdlib.h and unistd.h if available.
Include xalloc.h.
(xmalloc, xstrdup, free): Remove decls.
(xgetcwd): Don't assume sizes fit in unsigned.
Check for overflow when computing sizes.
Simplify reallocation code.
Also, make the following further changes to make this file's
configuration more similar to that of strtol.c:
(UNSIGNED): Renamed from STRTOUXMAX_UNSIGNED. All uses changed.
(strtoumax, uintmax_t, strtoull, strtol): Remove.
(intmax_t, strtoimax, strtol, strtoll): New macros, if UNSIGNED.
(strtoimax): Renamed from strtoumax. All uses of unsigned values
changed to signed values.
And make the following changes as well:
Fix copyright notice, as 1999 was missing.
(verify): New macro.
(strtoimax): Check sizes at compile-time, not run-time.
Prefer strtol to strtoll if both work.
(main): Remove; it was not that useful and was a pain to maintain.
