qt4: unset LD

Commit 093cc00cdd9d8cf31ecce5bc1dd3645c460a1b98 sets the `LD' environment
variable by default, interfering with the Makefile which uses gcc for linking.

+1
+1
pkgs/development/libraries/qt-4.x/4.8/default.nix
··· 114 114 -datadir $out/share/${name} 115 115 -translationdir $out/share/${name}/translations 116 116 " 117 + unset LD # Makefile uses gcc for linking; setting LD interferes 117 118 '' + optionalString stdenv.cc.isClang '' 118 119 sed -i 's/QMAKE_CC = gcc/QMAKE_CC = clang/' mkspecs/common/g++-base.conf 119 120 sed -i 's/QMAKE_CXX = g++/QMAKE_CXX = clang++/' mkspecs/common/g++-base.conf