gitk: Makefile: create install bin directory

Force creation of destination bin directory.  Without this, gitk
would fail to install if this directory didn't already exist.

Signed-off-by: Vasco Almeida <vascomalmeida@sapo.pt>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

Makefile

@@ -50,6 +50,7 @@ endif
 all:: gitk-wish $(ALL_MSGFILES)
 
 install:: all
+	$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$(bindir_SQ)'
 	$(INSTALL) -m 755 gitk-wish '$(DESTDIR_SQ)$(bindir_SQ)'/gitk
 	$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$(msgsdir_SQ)'
 	$(foreach p,$(ALL_MSGFILES), $(INSTALL) -m 644 $p '$(DESTDIR_SQ)$(msgsdir_SQ)' &&) true