Fix non _REENTRANT build.

Remove weak_alias since that's now in the compat_putenv.c

branches: 1.19.6; 1.19.12;
Improve and simplify implementation of *env(3) functions:
- Use RB tree to keep track of memory allocated via setenv(3) as
suggested by Enami Tsugutomo in private e-mail.
This simplifies the code a lot as we no longer need to keep the size
of "environ" in sync with an array of allocated environment variables.
It also makes it possible to free environment variables in unsetenv(3)
if something has changed the order of the "environ" array.
- Fix a bug in getenv(3) and getenv_r(3) which would return bogus
results e.g. for " getenv("A=B") " if an environment variable "A"
with value "B=C" exists.
- Clean up the internal functions:
- Don't expose the read/write lock for the environment to other parts
of "libc". Provide locking functions instead.
- Use "bool" to report success or failure.
- Use "ssize_t" or "size_t" instead of "int" for indexes.
- Provide internal functions with simpler interfaces e.g. don't
combine return values and reference arguments.
- Don't copy "environ" into an allocated block unless we really need
to grow it.

Code reviewed by Joerg Sonnenberger and Christos Zoulas, tested by
Joerg Sonnenberger and me. These changes also fix problems in
zsh 4.3.* and pam_ssh according to Joerg.

Handle the case where a program attempted to cleanup the environment by
setting *environ = NULL;

Make putenv(3) fails with EINVAL for a null pointer, or for a string
that either miss or start with a `=' character.

Adjust man page and testcase accordingly.

Avoid unnecessary malloc(). Since __findenv() kindly treats
equal sign as an end of string, we can pass the string of
form "key=value" to lookup "key".

Restore binary compatibility with applications which use putenv(3)
on constant strings (e.g. postdrop(1)):
- Don't write to the environment string passed to putenv(3).
- Don't overwrite the value of an existing environment string
unless the memory was actually allocated by setenv(3).

Remember that we didn't malloc() memory for an environment variable
if it has been set via putenv(3).

make putenv POSIX compliant.

Move UCB-licensed code from 4-clause to 3-clause licence.

Patches provided by Joel Baker in PR 22280, verified by myself.

Delint.
Remove trailing ; from uses of __weak_alias(). The macro inserts this if
needed.

back out the #ifdef _DIAGNOSTIC argument checks; too many people complained.
_DIAGASSERT() is still retained.

* use _DIAGASSERT() to check pointer arguments against NULL and file
descriptors against -1 (as appropriate).
* add actual checks which to detect stuff that would trigger_DIAGASSERT(),
and attempt to return a sane error condition.
* knf some code
* remove some `register' decls.

the first two items result in the addition of code similar to the
following in various functions:

_DIAGASSERT(path != NULL)
#ifdef _DIAGNOSTIC
if (path == NULL) {
errno = EFAULT;
return (-1);
}
#endif

update to lite-2

If port provides __weak_alias(), provide an Standard C and POSIX pure
identifier namespace by renaming non standard functions and variables
such that they have a leading underscore. The library will use those
names internally. Weak aliases are used to provide the original names
to the API.

This is only the first part of this change. It is most of the functions
which are implemented in C for all NetBSD ports. Subsequent changes are
to add the same support to the remaining C files, to assembly files, and
to the automagically generated assembly source used for system calls.
When all of the above is done, ports with weak alias support should add
a definition for __weak_alias to <sys/cdefs.h>.

Add local.h for local prototypes.
Fix namespace issues for strtoq and strtouq
Fix gcc warnings.
Fix RCSID's

branches: 1.5.2;
New-style RCS ids.

Change C library functions to use strchr() and strrchr() instead of index()
and rindex(). This will allow (strict {ANSI, POSIX, XOPEN}) applications
to redefine index() and rindex() without effecting the library internals.

Declare rcsid strings so they are stored in text segment.

Add RCS identifiers.

branches: 1.1.1;
Initial revision