uninstall: Remove empty libsigrok/libsigrokcxx include directories.

Change uninstall-local to uninstall-hook, since the latter is guaranteed
to run last (order is apparently not guaranteed for uninstall-local).

This fixes bug #861.

Makefile.am

@@ -601,6 +601,11 @@ INSTALL_EXTRA =
 UNINSTALL_EXTRA =
 CLEAN_EXTRA =
 
+libsigrok-uninstall:
+	-rmdir $(DESTDIR)$(includedir)/libsigrok
+
+UNINSTALL_EXTRA += libsigrok-uninstall
+
 if BINDINGS_CXX
 
 lib_LTLIBRARIES += bindings/cxx/libsigrokcxx.la
@@ -643,6 +648,11 @@ cxx-clean:
 
 CLEAN_EXTRA += cxx-clean
 
+cxx-uninstall:
+	-rmdir $(DESTDIR)$(includedir)/libsigrokcxx
+
+UNINSTALL_EXTRA += cxx-uninstall
+
 endif
 
 CPPXMLDOC = bindings/cxx/doxy/xml/index.xml
@@ -825,7 +835,7 @@ endif
 
 all-local: $(BUILD_EXTRA)
 install-exec-local: $(INSTALL_EXTRA)
-uninstall-local: $(UNINSTALL_EXTRA)
+uninstall-hook: $(UNINSTALL_EXTRA)
 clean-local: $(CLEAN_EXTRA)
 
 .PHONY: dist-changelog