OK to add qttools as a build dependency for all qt6 ports? We're doing
the same in qt5.port.mk.

I'm currently porting more and more Qt6 consumers that shows me that I
almost always need a tool from qttools.


Index: qt6.port.mk
===================================================================
RCS file: /cvs/ports/x11/qt6/qt6.port.mk,v
diff -u -p -r1.7 qt6.port.mk
--- qt6.port.mk	2 Sep 2023 08:25:20 -0000	1.7
+++ qt6.port.mk	17 Feb 2024 07:58:56 -0000
@@ -34,11 +34,15 @@ _MODQT6_SETUP +=	Qt6_DIR=${MODQT6_LIBDIR
 MODQT6_LIB_DEPENDS =	x11/qt6/qtbase
 MODQT_LIB_DEPENDS ?=	${MODQT6_LIB_DEPENDS}
 
+# qdoc, etc.
+MODQT6_BUILD_DEPENDS = 	x11/qt6/qttools
+
 MODQT_DEPS ?=		Yes
 MODQT6_DEPS ?=		${MODQT_DEPS}
 
 .if ${MODQT6_DEPS:L} == "yes"
 LIB_DEPENDS +=		${MODQT6_LIB_DEPENDS}
+BUILD_DEPENDS += 	${MODQT6_BUILD_DEPENDS}
 .endif
 
 CONFIGURE_ENV +=	${_MODQT6_SETUP}