* libc/stdlib/abort.c: changed description: uses "raise" instead of
"getpid" and "kill"; added: uses "write" and "_exit".
Also included unistd.h for "_exit" prototype.
* libc/stdlib/system.c: included unistd.h for "execve" prototype,
reent.h for "_fork_r" and "_wait_r" prototypes.
(do_system): changed extern char *environ[] to POSIX-friendly
extern char **environ.
* libc/stdlib/wctomb_r.c: included string.h for "strlen" and "strcmp"
prototypes.
* libc/stdlib/remove.c: included reent.h for "_unlink_r" prototype.
* libc/reent/execr.c: included sys/wait.h for "wait" prototype.
* libc/reent/fstatr.c: included sys/stat.h for "fstat" prototype.
* libc/reent/openr.c: included fcntl.h for "open" prototype.
* libc/reent/signalr.c: included signal.h for "kill" prototype,
unistd.h for "getpid" prototype.
* libc/reent/statr.c: included sys/stat.h for "stat" prototype.
* libc/reent/timer.c: included sys/time.h for "gettimeofday" prototype.
* libc/unix/getut.c (utmpname): removed local, incorrect "strdup"
prototype. Also included stdlib.h for "abort", string.h for
"strdup" and "strncmp" prototypes.
* libc/unix/getlogin.c: included string.h for "strncmp", "memset", and
"strncpy", unistd.h for "read" and "close" prototypes.
* libc/posix/execvp.c: included string.h for "strchr", "strlen", and
"strcat" prototypes.
Jordi Sanfeliu