glx,xquartz: Fix make distcheck

Guard BUILT_SOURCES and CLEANFILES by XWIN_GLX_WINDOWS/XQUARTZ.

hw/xquartz/mach-startup/Makefile.am

@@ -76,6 +76,8 @@ nodist_Xquartz_SOURCES = \
 Xquartz_LDFLAGS =  \
 	-Wl,-framework,CoreServices
 
+if XQUARTZ
+
 BUILT_SOURCES = \
 	mach_startupServer.c \
 	mach_startupUser.c \
@@ -88,6 +90,8 @@ CLEANFILES = \
 $(BUILT_SOURCES): $(srcdir)/mach_startup.defs
 	mig -sheader mach_startupServer.h $(srcdir)/mach_startup.defs
 
+endif
+
 EXTRA_DIST = \
 	launchd_fd.h \
 	mach_startup.defs \

hw/xwin/glx/Makefile.am

@@ -62,9 +62,10 @@ generated_gl_thunks.ic: $(srcdir)/gen_gl_wrappers.py $(KHRONOS_SPEC_DIR)/gl.xml
 
 generated_gl_thunks.def: $(srcdir)/gen_gl_wrappers.py $(KHRONOS_SPEC_DIR)/gl.xml $(KHRONOS_SPEC_DIR)/reg.py
 	$(AM_V_GEN)PYTHONPATH=$(KHRONOS_SPEC_DIR) $(PYTHON3) $(srcdir)/gen_gl_wrappers.py -registry $(KHRONOS_SPEC_DIR)/gl.xml -thunkdefs $(GENGLWRAPPERSOPTS) -outfile $@
-endif
 
 BUILT_SOURCES = generated_gl_shim.ic generated_gl_thunks.ic generated_gl_thunks.def generated_wgl_wrappers.ic
 CLEANFILES = $(BUILT_SOURCES)
 
+endif
+
 EXTRA_DIST = gen_gl_wrappers.py