that these calls be thread-safe with respect to the environment, and it
causes serious problems for threaded applications which call vfork() and
exec*() (including indirectly, via popen() or system()).
Acquire and release __environ_lock in the parent in popen() and system() to
play safe and provide the child with a stable environment.
__environ_lock should also have an atfork() handler; still under development.
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>.
