…se them

It is the only library we use that calls itself with 'lib' in the
name. This might be confusing, but with the arrival of cmake a lot
of these things are automated. And detection will find 'liblzma',
not 'lzma', like with 'lzo', 'zlib', ..

… files)

By naming it in a different way, things get a bit confusing.
Especially if we are switching to CMake, which autodetects these
things, we need to use the name the authors of ICU gave it; not
our interpertation of that name.

… files)

By naming it in a different way, things get a bit confusing.
Especially if we are switching to CMake, which autodetects these
things, we need to use the name the authors of ICU gave it; not
our interpertation of that name.

config.lib happens to set GLOBAL_DATA_DIR in case it is not DOS
and not OS2, but this kind of deduction is annoying to maintain.
It is better to just check if the define you want to use is set,
and leave it to config.lib to set it or not depending on the OS.

…viour

If it was compiled with MingW, both / and \ were accepted as
path separator. On MSVC, only \ was. This is an unexpected
difference between binaries for the same platform. Remove this
discrepancy by accepting both / and \ on all platforms.

This is more in trend with other files, where if the driver is not
selected, we don't even attempt to compile it.