[Nix-dev] CMake broken

[Peter Simons]

Hi,

the recent changes to the CMake expression break the build for me on
Linux/x86_64 when useNcurses is 'false'. This setting means that CMake
won't have ncurses in buildInputs, but the build seems to expect it
anyway and fails trying to compile ncurses-specific modules.

Generally speaking, I find these changes somewhat dubious. For instance, we
now have three different versions of CMake defined in all-packages.nix:

  cmake = callPackage ../development/tools/build-managers/cmake { };

  cmakeCurses = cmake.override { useNcurses = true; };

  cmakeWithGui = cmakeCurses.override { useQt4 = true; };

However, all of these expressions have the same name! That's an ambiguous
and undesirable situation. Also, where is the version that has support for
both qt and ncurses?

Last but not least, I'm not particularly fond of expressions that require
'useDepXY' flags. IMHO, it's both easier and more intuitive to pass 'xy =
null' to disable support for that particular dependency.

Take care,
Peter