texmacs: 1.99.2 -> 1.99.10

Packaging changes:

* Switch from autoconf to cmake.
  Fixes error
      checking for guile-config... guile-config
      sh: =~: unknown operand
      ./configure: ./configure.lineno: line 8057: syntax error: bad substitution
  that appared with the new version.
* Also add new dependencies for new features: git, python
  * (fixes all "missing" errors in cmake's output)
* Stay at Qt4 for now to not introduce too many changes
  * Upgrading to Qt5 in the future is feasible (#33248); it builds
  * I'm not doing it here because Qt5 apps apparently don't run yet on non-NixOS