Make several global variables static.
#ifdef definitions of rarely unused functions.
* defs.h (rflag, tflag, outfname): Remove.
* strace.c (iflag, interactive, pflag_seen, rflag, tflag,
outfname, username): Make static.
* desc.c (sys_getdtablesize): Define only for
ALPHA || FREEBSD || SUNOS4.
* file.c (sys_fchroot): Define only for SUNOS4 || SVR4.
(sys_mkfifo): Define only for FREEBSD.
* mem.c (sys_sbrk): Define only for FREEBSD || SUNOS4.
(sys_getpagesize): Define only for
ALPHA || FREEBSD || IA64 || SUNOS4 || SVR4.
* net.c (sys_so_socket): Define only for SVR4.
* process.c (sys_gethostid): Define only for
FREEBSD || SUNOS4 || SVR4.
(sys_gethostname): Define only for
ALPHA || FREEBSD || SUNOS4 || SVR4.
(sys_setpgrp): Define only for ALPHA || SUNOS4 || SVR4.
(sys_execv): Define only for SPARC || SPARC64 || SUNOS4.
* signal.c (sys_sigblock): Define only for FREEBSD || SUNOS4.
(sys_sighold, sys_sigwait): Define only for SVR4.
(sys_killpg): Define only for FREEBSD || SUNOS4.
* stream.c (sys_getmsg): Define only for
SPARC || SPARC64 || SUNOS4 || SVR4.
* syscall.c (sys_indir): Define only for SUNOS4.