* misc/getusershell.c: Make strings in okshells array const.
* misc/regexp.c: Add const to cast to avoid warnings.
* sysdeps/unix/sysv/linux/llseek.c: Add prototype for __llseek.
* sysdeps/unix/sysv/linux/i386/setresuid.c: Add prototype for
__setresuid.
* sysdeps/unix/sysv/linux/i386/setresgid.c: Add prototype for
setresgid.
* misc/error.c: Add prototypes for __error and __error_at_line.
* misc/mntent_r.c (__getmntent_r): Add break at end of switch
statement to avoid warning.