Don't save "warning: " prefix in lastwarn() message. * error.cc (vwarning): Save base_msg (without "warning: ") to Vlast_warning_message. * error.cc (error_1): Use std::string operators rather than strsave to strip "\n" from fmt string. Simpler syntax avoids having to delete [] memory created with new. * error.cc (warning_1): Strip trailing newline from fmt string as error_1 does. * fail.m: Fix input validation which allowed nonsensical second input with 3 args. Don't post-process warning or error messages from lastwarn or lasterr. Add BIST test for input validation.

#!/bin/sh
#
# Like mv $1 $2, but if the files are the same, just delete $1.
# Status is 0 if $2 is changed, 1 otherwise.

if test -r $2; then
  if cmp $1 $2 > /dev/null; then
    echo $2 is unchanged
    rm -f $1
  else
    mv -f $1 $2
  fi
else
  mv -f $1 $2
fi