Revert "qt56.qtbase: apply CMake setup-hook fix locally"

This reverts commit 6b6f067397db8b9a3a051ad6616206871acf098c.

pkgs/development/libraries/qt-5/5.6/qtbase/setup-hook.sh

@@ -141,17 +141,4 @@ _qtLinkAllModules() {
     done
 }
 
-_qtFixCMake() {
-    for flag in $NIX_CFLAGS_COMPILE $NIX_LDFLAGS; do
-        case $flag in
-            -L*)
-                CMAKE_INSTALL_RPATH="$CMAKE_INSTALL_RPATH${CMAKE_INSTALL_RPATH:+:}${flag:2}"
-                ;;
-        esac
-    done
-    cmakeFlags="-DCMAKE_BUILD_WITH_INSTALL_RPATH=TRUE $cmakeFlags"
-    cmakeFlags="-DCMAKE_INSTALL_RPATH_USE_LINK_PATH=FALSE $cmakeFlags"
-    cmakeFlags="-DCMAKE_INSTALL_RPATH=$CMAKE_INSTALL_RPATH $cmakeFlags"
-}
-
-preConfigureHooks+=(_qtLinkAllModules _qtFixCMake)
+preConfigureHooks+=(_qtLinkAllModules)