Package QGIS 2.18 for darwin

There are still some problems with the withGrass option but the package
is mostly functional.

pkgs/applications/gis/qgis/default.nix

@@ -1,23 +1,31 @@
 { stdenv, fetchurl, fetchpatch, gdal, cmake, qt4, flex, bison, proj, geos, xlibsWrapper, sqlite, gsl
 , qwt, fcgi, python2Packages, libspatialindex, libspatialite, qscintilla, postgresql, makeWrapper
-, qjson, qca2, txt2tags, openssl
-, withGrass ? false, grass
+, qjson, qca2, txt2tags, openssl, darwin, pkgconfig
+, withGrass ? false, grass, IOKit, ApplicationServices
 }:
 
 stdenv.mkDerivation rec {
   name = "qgis-2.18.16";
 
   buildInputs = [ gdal qt4 flex openssl bison proj geos xlibsWrapper sqlite gsl qwt qscintilla
-    fcgi libspatialindex libspatialite postgresql qjson qca2 txt2tags ] ++
+    fcgi libspatialindex libspatialite postgresql qjson qca2 txt2tags pkgconfig ]
+  ++
+    (stdenv.lib.optionals stdenv.isDarwin [IOKit ApplicationServices])
+  ++
     (stdenv.lib.optional withGrass grass) ++
+    (stdenv.lib.optional (stdenv.isDarwin && withGrass) darwin.apple_sdk.libs.utmp) ++
     (with python2Packages; [ jinja2 numpy psycopg2 pygments requests python2Packages.qscintilla sip ]);
 
-  nativeBuildInputs = [ cmake makeWrapper ];
+  nativeBuildInputs = [ cmake makeWrapper pkgconfig ];
 
   # `make -f src/providers/wms/CMakeFiles/wmsprovider_a.dir/build.make src/providers/wms/CMakeFiles/wmsprovider_a.dir/qgswmssourceselect.cpp.o`:
   # fatal error: ui_qgsdelimitedtextsourceselectbase.h: No such file or directory
   enableParallelBuilding = false;
 
+  preConfigure = ''
+    NIX_CFLAGS_COMPILE="$NIX_CFLAGS_COMPILE $(pkg-config --cflags libspatialindex)"
+  '';
+
   # To handle the lack of 'local' RPATH; required, as they call one of
   # their built binaries requiring their libs, in the build process.
   preBuild = ''
@@ -29,19 +37,44 @@ stdenv.mkDerivation rec {
     sha256 = "0d880m013kzi4qiyr27yjx6hzpb652slp66gyqgw9ziw03wy12c9";
   };
 
-  cmakeFlags = stdenv.lib.optional withGrass "-DGRASS_PREFIX7=${grass}/${grass.name}";
+  # CMAKE_FIND_FRAMEWORK=never stops the installer choosing system
+  # installed frameworks
+  # QGIS_MACAPP_BUNDLE=0 stops the installer copying the Qt binaries into the
+  # installation which causes havoc
+  # Building RelWithDebInfo allows QGIS_DEBUG to print debugging information
+  cmakeFlags = stdenv.lib.optional withGrass "-DGRASS_PREFIX7=${grass}/${grass.name}"
+               ++ stdenv.lib.optional stdenv.isDarwin
+                    (["-DCMAKE_FIND_FRAMEWORK=never"]
+                      ++ ["-DQGIS_MACAPP_BUNDLE=0"]);
+#                     ++ ["-DCMAKE_BUILD_TYPE=RelWithDebInfo"];
 
-  postInstall = ''
-    wrapProgram $out/bin/qgis \
-      --prefix PYTHONPATH : $PYTHONPATH \
-      --prefix LD_LIBRARY_PATH : ${stdenv.lib.makeLibraryPath [ openssl ]}
-  '';
+
+
+  postInstall =
+    (stdenv.lib.optionalString stdenv.isLinux ''
+          wrapProgram $out/bin/qgis \
+            --set PYTHONPATH $PYTHONPATH \
+            --prefix LD_LIBRARY_PATH : ${stdenv.lib.makeLibraryPath [ openssl ]}
+          '') +
+    (stdenv.lib.optionalString stdenv.isDarwin ''
+      # Necessary for QGIS to find the correct default GRASS path
+      ${stdenv.lib.optionalString withGrass "ln -sf ${grass} $out/QGIS.app/Contents/MacOS/grass"}
+      for file in $(find $out -type f -name "QGIS"); do
+        wrapProgram "$file" \
+          --prefix DYLD_LIBRARY_PATH : "${qwt}/lib" \
+          --prefix DYLD_LIBRARY_PATH : "${qscintilla}/lib" \
+          ${stdenv.lib.optionalString withGrass "--prefix PATH : ${grass}/bin"} \
+          --set PYTHONPATH $PYTHONPATH
+      done
+      mkdir -p $out/bin
+      ln -s $out/QGIS.app/Contents/MacOS/QGIS $out/bin/qgis
+      '');
 
   meta = {
     description = "User friendly Open Source Geographic Information System";
     homepage = http://www.qgis.org;
     license = stdenv.lib.licenses.gpl2Plus;
-    platforms = with stdenv.lib.platforms; linux;
+    platforms = with stdenv.lib.platforms; unix;
     maintainers = with stdenv.lib.maintainers; [viric];
   };
 }

pkgs/top-level/all-packages.nix

@@ -17225,7 +17225,9 @@ with pkgs;
 
   qemu-riscv = callPackage ../applications/virtualization/qemu/riscv.nix {};
 
-  qgis = callPackage ../applications/gis/qgis {};
+  qgis = callPackage ../applications/gis/qgis {
+    inherit (darwin.apple_sdk.frameworks) IOKit ApplicationServices;
+  };
 
   qgroundcontrol = libsForQt5.callPackage ../applications/science/robotics/qgroundcontrol { };