make distcheck: bypass kde4-config

distcheck uses --prefix instead of DESTDIR :(
(cherry picked from commit 9922f5d3)

Makefile.am

@@ -98,7 +98,8 @@ DISTCHECK_CONFIGURE_FLAGS = \
 	--disable-mad --disable-libmpeg2 \
 	--disable-faad --disable-skins2 \
 	--disable-live555 \
-	--disable-fribidi --disable-glx
+	--disable-fribidi --disable-glx \
+	--with-kde-solid='$(datadir)/kde4/apps'
 
 ACLOCAL_AMFLAGS = -I m4
 AUTOMAKE_OPTIONS = \