store errno on the private process stack so its always per process
and not just per memory space. errno itself becomes a macro
dereferencing int *_errnoloc; which is initialized from main9.s
pointing to the private stack location.
various fixes in programs that just imported errno variable with
"extern int errno;" instead of including <errno.h>.
_grpmems() was broken tokenizing group list in place.
we have to copy it to status buffer before tokenizing.
dynamically alloc path for test file to check write
permission on directory and add pid to the name to
prevent races.
use _OPEN instead of ape open to read /dev/ppid in
getppid().
use mode enums instead of numeric constants for _OPEN()
and _CREATE().
remove envname length limitation in _envsetup()
by using allocated buffer and use /env instead of #e
use /proc and getpid() instead of #p and #c in
readprocfdinit()
fix buffer overflow in execlp(), check if name
of failed exec starts with / . or is \0
make sure not to close our own filedescriptors
for FD_CLOEXEC in execve(), fix wrong length
check for flushing buffer to /env/_fdinfo.
fix error handling cases. copy the enviroment
before decoding \1 to \0 because the strings in
environ[] array might not be writable.
remove bogus close if we fail to open ppid file
in getppid() and use /dev/ppid instead of #c/ppid
