Makefile: remove $foo when $foo.exe is built/installed.

On Cygwin, newly builtins are not recognized, because there exist both
the executable binaries (with .exe extension) _and_ the now-obsolete
scripts (without extension), but the script is executed.

Signed-off-by: Junio C Hamano <junkio@cox.net>

Makefile

@@ -1,5 +1,5 @@
 # The default target of this Makefile is...
-all:
+all::
 
 # Define NO_OPENSSL environment variable if you do not have OpenSSL.
 # This also implies MOZILLA_SHA1.
@@ -605,9 +605,12 @@ export prefix TAR INSTALL DESTDIR SHELL_PATH template_dir
 
 ### Build rules
 
-all: $(ALL_PROGRAMS) $(BUILT_INS) git$X gitk gitweb/gitweb.cgi
+all:: $(ALL_PROGRAMS) $(BUILT_INS) git$X gitk gitweb/gitweb.cgi
+ifneq (,$X)
+	$(foreach p,$(patsubst %$X,%,$(filter %$X,$(ALL_PROGRAMS) $(BUILT_INS) git$X)), rm -f '$p';)
+endif
 
-all:
+all::
 	$(MAKE) -C perl PERL_PATH='$(PERL_PATH_SQ)' prefix='$(prefix_SQ)' all
 	$(MAKE) -C templates
 
@@ -849,6 +852,9 @@ install: all
 			'$(DESTDIR_SQ)$(gitexecdir_SQ)/git$X'; \
 	fi
 	$(foreach p,$(BUILT_INS), rm -f '$(DESTDIR_SQ)$(gitexecdir_SQ)/$p' && ln '$(DESTDIR_SQ)$(gitexecdir_SQ)/git$X' '$(DESTDIR_SQ)$(gitexecdir_SQ)/$p' ;)
+ifneq (,$X)
+	$(foreach p,$(patsubst %$X,%,$(filter %$X,$(ALL_PROGRAMS) $(BUILT_INS) git$X)), rm -f '$(DESTDIR_SQ)$(gitexecdir_SQ)/$p';)
+endif
 
 install-doc:
 	$(MAKE) -C Documentation install