Change:
<del> { lib, stdenv , fetchgit , alsa-lib , aubio , boost , cairomm , curl , doxygen , fftwSinglePrec , flac , glibmm , graphviz , gtkmm2 , libjack2 , liblo , libogg , libsamplerate , libsigcxx , libsndfile , libusb1 , fluidsynth_1 , hidapi , libltc , qm-dsp , libxml2 , lilv , lrdf , lv2 , perl , pkg-config , itstool , python2 , rubberband , serd , sord , sratom , taglib , vamp-plugin-sdk , dbus , fftw , pango , suil , libarchive , wafHook }: let # Ardour git repo uses a mix of annotated and lightweight tags. Annotated # tags are used for MAJOR.MINOR versioning, and lightweight tags are used # in-between; MAJOR.MINOR.REV where REV is the number of commits since the # last annotated tag. A slightly different version string format is needed # for the 'revision' info that is built into the binary; it is the format of # "git describe" when _not_ on an annotated tag(!): MAJOR.MINOR-REV-HASH. # Version to build. tag = "5.12"; in stdenv.mkDerivation rec { pname = "ardour_5"; version = "5.12"; src = fetchgit { url = "git://git.ardour.org/ardour/ardour.git"; rev = "ae0dcdc0c5d13483271065c360e378202d20170a"; sha256 = "0mla5lm51ryikc2rrk53max2m7a5ds6i1ai921l2h95wrha45nkr"; }; nativeBuildInputs = [ wafHook pkg-config itstool doxygen graphviz # for dot perl python2 ]; buildInputs = [ alsa-lib aubio boost cairomm curl dbus fftw fftwSinglePrec flac glibmm gtkmm2 libjack2 liblo libogg libsamplerate libsigcxx libsndfile libusb1 fluidsynth_1 hidapi libltc qm-dsp libxml2 lilv lrdf lv2 pango rubberband serd sord sratom suil taglib vamp-plugin-sdk libarchive ]; wafConfigureFlags = [ "--optimize" "--docs" "--use-external-libs" "--freedesktop" "--with-backends=jack,alsa,dummy" ]; NIX_CFLAGS_COMPILE = "-I${qm-dsp}/include/qm-dsp"; # ardour's wscript has a "tarball" target but that required the git revision # be available. Since this is an unzipped tarball fetched from github we # have to do that ourself. postPatch = '' printf '#include "libs/ardour/ardour/revision.h"nnamespace ARDOUR { const char* revision = "${tag}-${builtins.substring 0 8 src.rev}"; }n' > libs/ardour/revision.cc patchShebangs ./tools/ ''; postInstall = '' # wscript does not install these for some reason install -vDm 644 "build/gtk2_ardour/ardour.xml"  -t "$out/share/mime/packages" install -vDm 644 "build/gtk2_ardour/ardour5.desktop"  -t "$out/share/applications" for size in 16 22 32 48 256 512; do install -vDm 644 "gtk2_ardour/resources/Ardour-icon_''${size}px.png"  "$out/share/icons/hicolor/''${size}x''${size}/apps/ardour5.png" done install -vDm 644 "ardour.1"* -t "$out/share/man/man1" ''; meta = with lib; { description = "Multi-track hard disk recording software"; longDescription = '' Ardour is a digital audio workstation (DAW), You can use it to record, edit and mix multi-track audio and midi. Produce your own CDs. Mix video soundtracks. Experiment with new ideas about music and sound. Please consider supporting the ardour project financially: https://community.ardour.org/donate ''; homepage = "https://ardour.org/"; license = licenses.gpl2; platforms = platforms.linux; maintainers = with maintainers; [ goibhniu fps ]; }; } </del>

Discussion:
fails to build as There is an invasive change that fixed it in newer version: . But maybe it's a good time to remove old version? Maintainer information:
Started with commit
Is there a reason to still keep Ardour 5.x in nixpkgs? Edit: The reads: Is that still the case ?
Yes it is, but I'm not sure it's worth the effort to fix Ardour 5.
I prepared a PR which drops ardour_5 if we decide to go this way: