In some cases, such as when building cross compilers, the binaries and
manpages contain the target architecture tuple, such as
`i686-w64-mingw32-g++.1`.
Ensure the symlink created to save space with the duplicated manpage
(`g++.1 -> gcc.1`) properly handles such cases and generates symlinks
such as `i686-w64-mingw32-g++.1 -> i686-w64-mingw32-gcc.1`.
Previously in such cases, a broken `gcc.1` link would be created
instead.
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