libvterm: fix cross compilation

pkgs/development/libraries/libvterm/default.nix

···
     sha256 = "10gaqygmmwp0cwk3j8qflri5caf8vl3f7pwfl2svw5whv8wkn0k2";
   };
 
-  patchPhase = ''
-    sed -i -e s@/usr@$out@ -e /ldconfig/d Makefile
+  preInstall = ''
+    mkdir -p $out/include $out/lib
   '';
 
-  preInstall = ''
-    mkdir -p $out/include
-    mkdir -p $out/lib
+  postPatch = ''
+    substituteInPlace Makefile \
+      --replace "gcc" "${stdenv.cc.targetPrefix}cc" \
+      --replace "ldconfig" "" \
+      --replace "/usr" "$out"
+
+    makeFlagsArray+=("PKG_CFG=`${stdenv.cc.targetPrefix}pkg-config --cflags glib-2.0`")
   '';
 
+  # For headers
+  propagatedBuildInputs = [ glib ];
+
+  strictDeps = true;
+
   nativeBuildInputs = [ pkg-config ];
-  buildInputs = [ glib ncurses ];
+  buildInputs = [ ncurses ];
 
   meta = with lib; {
     homepage = "http://libvterm.sourceforge.net/";