separate macro. Also add support for %I64d which is the way on Windows.
The code that checks for the 64-bit int type now gives more reasonable
results when cross-compiling: In that case we just take the compiler's
information and trust that the arithmetic works. Disabling int64 is too
pessimistic.
Interfaced a lot of the custom tests to the config.cache, in the process
made them separate macros and grouped them out into files. Made naming
adjustments.
Removed a couple of useless/unused configure tests.
Disabled C++ by default. C++ is no more special than Perl, Python, and Tcl.
And it breaks equally often. :(