remove awful pkg-config kludge, use depwBuildBuld

pkgs/modem-manager/default.nix

@@ -58,6 +58,10 @@
     bash # shebangs in share/ModemManager/fcc-unlock.available.d/
   ];
 
+  depsBuildBuild = [
+    pkg-config
+  ];
+
   mesonFlags = [
     "-Dudevdir=${placeholder "out"}/lib/udev"
     "-Ddbus_policy_dir=${placeholder "out"}/share/dbus-1/system.d"
@@ -75,14 +79,4 @@
     "-Dintrospection=false"
   ];
 
-  postPatch = ''
-    env | grep PKG
-    mkdir bin
-    PATH=${buildPackages.pkg-config}/bin:$PATH
-    PATH=$PWD/bin:$PATH
-    ln -s ${buildPackages.pkg-config}/bin/$PKG_CONFIG bin/pkg-config
-    echo $PATH | sed 's/:/\n/g' | grep pkg
-    type pkg-config
-    patchShebangs tools/test-modemmanager-service.py
-  '';
 }