Upstream changes:
- Fix markup typo in the man page.
- Abort on line numbering or column numbering overflow. Line
numbers are limited to values that fit in "unsigned int". Also
reject input lines longer than 2^32-1 characters. It seems
reasonable to presume that any input that violates these
constraints is someone screwing around and not a serious attempt
to compile or preprocess anything useful. Done in response to
n2129, but without getting into any of the silliness found there.
- Recognize __ia64__ for IA64 builds.
- Recognize __aarch64__ for 64-bit ARM builds, as sent in by
various people.
- Recognize __riscv__ and __riscv64__ for risc-v builds.
1a227ab0ea