perl/Makefile: move "mkdir -p" to module installation loop for maintainability

In the NO_PERL_MAKEMAKER=YesPlease fallback case, make the directory
that will contain each module when installing it (simulating "install
-D") instead of hardcoding "Git/SVN/Memoize is the deepest level".
This should make this codepath which is not used often on development
machines a little easier to maintain.

Requested-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

perl/Makefile

@@ -34,22 +34,34 @@ modules += Git/SVN/Ra
 
 $(makfile): ../GIT-CFLAGS Makefile
 	echo all: private-Error.pm Git.pm Git/I18N.pm > $@
-	echo '	mkdir -p blib/lib/Git/SVN/Memoize' >> $@
 	set -e; \
 	for i in $(modules); \
 	do \
+		if test $$i = $${i%/*}; \
+		then \
+			subdir=; \
+		else \
+			subdir=/$${i%/*}; \
+		fi; \
 		echo '	$(RM) blib/lib/'$$i'.pm' >> $@; \
+		echo '	mkdir -p blib/lib'$$subdir >> $@; \
 		echo '	cp '$$i'.pm blib/lib/'$$i'.pm' >> $@; \
 	done
 	echo '	$(RM) blib/lib/Error.pm' >> $@
 	'$(PERL_PATH_SQ)' -MError -e 'exit($$Error::VERSION < 0.15009)' || \
 	echo '	cp private-Error.pm blib/lib/Error.pm' >> $@
 	echo install: >> $@
-	echo '	mkdir -p "$$(DESTDIR)$(instdir_SQ)/Git/SVN/Memoize"' >> $@
 	set -e; \
 	for i in $(modules); \
 	do \
+		if test $$i = $${i%/*}; \
+		then \
+			subdir=; \
+		else \
+			subdir=/$${i%/*}; \
+		fi; \
 		echo '	$(RM) "$$(DESTDIR)$(instdir_SQ)/'$$i'.pm"' >> $@; \
+		echo '	mkdir -p "$$(DESTDIR)$(instdir_SQ)'$$subdir >> $@; \
 		echo '	cp '$$i'.pm "$$(DESTDIR)$(instdir_SQ)/'$$i'.pm"' >> $@; \
 	done
 	echo '	$(RM) "$$(DESTDIR)$(instdir_SQ)/Error.pm"' >> $@