Makefile: deactivate perl scripts unless server configuration is active

* doc/Makefile: Do not use perl scripts in util/ unless the server
  configuration $(SERVERMK) is set.

doc/Makefile

@@ -15,6 +15,7 @@ pdf:		org.pdf orgguide.pdf
 
 card:		orgcard.pdf orgcard_letter.pdf orgguide.pdf
 
+ifneq ($(SERVERMK),)
 manual guide::
 	-$(RMR) $@
 	$(MKDIR) $@
@@ -24,6 +25,7 @@ manual::	org.texi org-version.inc
 guide::		orgguide.texi org-version.inc
 	$(TEXI2HTML) -o $@ $<
 	../utils/guidesplit.pl $@/*
+endif
 
 org-version.inc:	org.texi
 	@echo "org-version: $(ORGVERSION) ($(GITVERSION))"
@@ -61,10 +63,12 @@ clean-install:
 
 %.html:		%.texi org-version.inc
 	$(TEXI2HTML) --no-split -o $@ $<
+ifneq ($(SERVERMK),)
 	../utils/manfull.pl $@
 
 %.txt:		%.tex
 	perl ../utils/orgcard2txt.pl $< > $@
+endif
 
 %_letter.tex:	%.tex
 	$(BATCH) \