kde.mk: Support KDE ports with no DOCS

The kde.mk framework automatically does DOCS for KDE ports --
but not all of them have documentation, so then you get a
weird situation of OPTIONS_DEFINE=DOCS in a port that has
no documentation (e.g. sysutils/baloo-widgets) where the
option has no effect at all.

Massage the machinery a little so that the bogus option can
be dropped; KDE ports with no docs should not define a DOCS
option any more.

PR:		252363

Mk/Uses/kde.mk

@@ -155,9 +155,14 @@ MASTER_SITES?=		KDE/${KDE_APPLICATIONS_BRANCH}/applications/${KDE_APPLICATIONS_V
 MASTER_SITES?=		KDE/${KDE_APPLICATIONS_BRANCH}/release-service/${KDE_APPLICATIONS_VERSION}/src
 # Let bsd.port.mk create the plist-entries for the documentation.
 # KDE Applications ports install their documentation to
-# ${PREFIX}/share/doc.
+# ${PREFIX}/share/doc. This is only done if the port
+# defines OPTION DOCS -- the _KDE_OPTIONS here is to
+# avoid make errors when there are no options defined at all.
+_KDE_OPTIONS=		bogus ${OPTIONS_DEFINE}
+.          if ${_KDE_OPTIONS:MDOCS}
 DOCSDIR=		${PREFIX}/share/doc
 PORTDOCS?=		HTML/*
+.          endif
 # Further pass along a SHLIB_VER PLIST_SUB
 PLIST_SUB+=		KDE_APPLICATIONS_SHLIB_VER=${KDE_APPLICATIONS_SHLIB_VER} \
 			KDE_APPLICATIONS_VERSION_SHORT="${KDE_APPLICATIONS_VERSION:R:R}"

sysutils/baloo-widgets/Makefile

@@ -13,8 +13,6 @@ USE_QT=		concurrent core dbus gui network testlib widgets xml \
 		buildtools_build qmake_build
 USE_LDCONFIG=	yes
 
-OPTIONS_DEFINE=	DOCS
-
 # Override shared library version
 KDE_APPLICATIONS_SHLIB_VER=${KDE_APPLICATIONS_VERSION}