Ensure more packages are built correctly

[fingolfin]

Several of them don't build right, or worse: may or may not build, depending on what is installed on the system. The relevant dependencies should be made explicit then.

Here is an excerpt of GAP's INSTALL.md:

Note that several of the packages bundled with GAP have additional
prerequisites. Here is an incomplete list of GAP packages and their requirements
(excluding GMP, which many packages require):

• 4ti2Interface
  • Debian/Ubuntu: 4ti2
  • Homebrew: (not currently available)
• alnuth
  • Debian/Ubuntu: pari-gp
  • Homebrew: pari
• browse
  • Debian/Ubuntu: libncurses-dev
  • Homebrew: ncurses
• CddInterface
  • Debian/Ubuntu: libcdd-dev
  • Homebrew: cddlib
• curlInterface
  • Debian/Ubuntu: libcurl4-openssl-dev
  • Homebrew: curl
• float
  • Debian/Ubuntu: libfplll-dev libmpc-dev libmpfi-dev libmpfr-dev
  • Homebrew: fplll libmpc mpfi mpfr
• singular
  • Debian/Ubuntu: singular
  • Homebrew: singular
• ZeroMQInterface
  • Debian/Ubuntu: libzmq3-dev
  • Homebrew: zmq

[dimpase]

why not just listing these as dependencies, too? it's cheap.

(as far as curl is concerned, probably the one from macOS can be used)