Add -vv option for listing supported features

[tueda]

This is a C++11 implementation of #645, adding a new command-line option -vv that prints supported/enabled (+) and unsupported/disabled (-) features. It also reports (runtime) library versions.

Example:

FORM 5.0.0-beta.1 (Jan 23 2026, v5.0.0-beta.1-318-gb18dc53)
-backtrace  +flint=3.4.0  +gmp=6.3.0   -mpi    -pthreads  +zlib=1.3.1
+debugging  +float        +mpfr=4.2.2  +posix  -windows   +zstd=1.5.7
  0.00 sec out of 0.00 sec

[jodavies]

This looks nice, it would be good to merge for v5. We can prompt people to include this information in bug reports.

[coveralls]

coverage: 57.846% (-0.05%) from 57.893%
when pulling a27c45c on tueda:pr/feat/print-feature-list
into eb24708 on form-dev:master.

[tueda]

For use in bug reports, would it be helpful to include further information? (WIP branch)

FORM 5.0.0-beta.1 (Jan 24 2026, v5.0.0-beta.1-320-g74618ed)
-backtrace  +flint=3.3.1  +gmp=6.3.0   -mpi    -pthreads  +zlib=1.3.1
+debugging  +float        +mpfr=4.2.2  +posix  -windows   +zstd=1.5.7
Compiler: GCC 15.2.0
Architecture: arm64
  0.00 sec out of 0.00 sec

[jodavies]

Sure, the more information the better