this proved not useful after all
Only use `long long` and `long double` in content tests when truly necessary.

The default mode for many compilers includes warnings for any use of
`long long`, which we turn into errors.  It's fine for this to cause
C99 functions with `long long` in their official signature to be
unusable in C89 modes, but it shouldn't affect things like `snprintf`
which can be used without `long long`.

Also give this treatment to `long double`, even though it *was* in C89
and I haven't yet tripped over a compiler that complains about it,
because it wasn't thoroughly integrated into the library before C99.
scansys.py can *finally* take inventories as intended.

Some ergonomic improvements will still be coming, but we believe
the data collection and the output format are now finalized.
Junk all prior inventories and add a new glibc2.17-gcc48.

The new inventory format is sufficiently different from the old
one that there is no point even trying to map them across.
fix small logic error