contrib: qt: only run win-specific for windows

qwindows.a will only be present if building for windows, and the other
commands are irrelevant if we are not.

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

contrib/src/qt/rules.mak

@@ -63,6 +63,7 @@ QT_CONFIG += -release
 	cd $< && $(MAKE) -C src sub-moc-install_subtargets sub-rcc-install_subtargets sub-uic-install_subtargets
 	# Install plugins
 	cd $< && $(MAKE) -C src/plugins sub-platforms-install_subtargets
+ifdef HAVE_WIN32
 	mv $(PREFIX)/plugins/platforms/libqwindows.a $(PREFIX)/lib/ && rm -rf $(PREFIX)/plugins
 	# Move includes to match what VLC expects
 	mkdir -p $(PREFIX)/include/QtGui/qpa
@@ -73,6 +74,7 @@ QT_CONFIG += -release
 	cd $(PREFIX)/lib/pkgconfig; for i in Qt5Core.pc Qt5Gui.pc Qt5Widgets.pc; do sed -i.orig -e 's/d\.a/.a/g' -e 's/d $$/ /' $$i; done
 	# Fix Qt5Gui.pc file to include qwindows (QWindowsIntegrationPlugin) and platform support libraries
 	cd $(PREFIX)/lib/pkgconfig; sed -i.orig -e 's/ -lQt5Gui/ -lqwindows -ldwmapi -lQt5ThemeSupport -lQt5FontDatabaseSupport -lQt5EventDispatcherSupport -lQt5WindowsUIAutomationSupport -lqtfreetype -lQt5Gui/g' Qt5Gui.pc
+endif
 ifdef HAVE_CROSS_COMPILE
 	# Building Qt build tools for Xcompilation
 	cd $</include/QtCore; ln -sf $(QT_VERSION)/QtCore/private