Build Failure after 'make clean'

Building and running from git. libxfce4ui build fails after 'make clean' since 4.19.0? (I don't recall it happening before then):

make[3]: Entering directory '/home/toz/Development/Xfce.gitlab/libxfce4ui/glade'
  CC       libxfce4uiglade2_la-libxfce4ui-glade.lo
  CCLD     libxfce4uiglade2.la
make[3]: *** No rule to make target 'libxfce4ui-2.xml', needed by 'all-am'.  Stop.
make[3]: Leaving directory '/home/toz/Development/Xfce.gitlab/libxfce4ui/glade'
make[2]: *** [Makefile:688: all-recursive] Error 1
make[2]: Leaving directory '/home/toz/Development/Xfce.gitlab/libxfce4ui/glade'
make[1]: *** [Makefile:538: all-recursive] Error 1
make[1]: Leaving directory '/home/toz/Development/Xfce.gitlab/libxfce4ui'
make: *** [Makefile:470: all] Error 2

'make clean' deletes that file:

make[2]: Entering directory '/tmp/libxfce4ui/glade'
test -z "libxfce4ui-2.xml" || rm -f libxfce4ui-2.xml