* lib/error.c, lib/error.h, lib/msvc-inval.c, lib/msvc-inval.h,
lib/msvc-nothrow.c, lib/msvc-nothrow.h, m4/error.m4, m4/msvc-inval.m4,
m4/msvc-nothrow.m4: New files from gnulib
1af55d85d9762a679b4302d5995f05ccd883e956.
* lib/Makefile.am, m4/gnulib-cache.m4, m4/gnulib-comp.m4: Adjust.
* src/bin/ltlfilt.cc: Use error() and error_at_line().