build: remove unused QMAKE_* VARs

As far as I can gather Qts build system doesn't respect either of these
variables (there is a QMAKE_LIBTOOL_LIBDIR).

Author: fanquake

depends/patches/qt/mac-qmake.conf

@@ -19,6 +19,4 @@ QMAKE_MAC_SDK.macosx.PlatformPath = /phony
 !host_build: QMAKE_LFLAGS += -target $${MAC_TARGET}
 QMAKE_AR = $${CROSS_COMPILE}ar cq
 QMAKE_RANLIB=$${CROSS_COMPILE}ranlib
-QMAKE_LIBTOOL=$${CROSS_COMPILE}libtool
-QMAKE_INSTALL_NAME_TOOL=$${CROSS_COMPILE}install_name_tool
 load(qt_config)