added entry for PDF

doc/Makefile

 # webpage update
 RDIR = teuben@apus:/apus1/nemo/local/www/amnh
 EXPORT = partiview*html partiview.ps partiview.sgml partiview.txt \
-	                partiview2.ps
+	                partiview2.ps partiview.pdf
 
 help:
 	@echo all:  ps html
@@ -10,9 +10,9 @@ help:
 	@echo EXPORT=$(EXPORT)
 	@echo RDIR=$(RDIR)
 
-.PHONY:  txt ps html
+.PHONY:  txt ps pdf html
 
-all:    txt ps html 
+all:    txt ps pdf html 
 
 txt:
 	sgml2txt partiview.sgml
@@ -23,6 +23,10 @@ ps:
 	gzip -c partiview.ps > partiview.ps.gz
 	rm partiview.dvi
 
+# 	note ps2pfg as well as pstopdf exist
+pdf:
+	ps2pdf partiview.ps
+
 #		need psutils for pnsup (prints 2 pages on 1)
 ps2:	ps
 	psnup -2 partiview.ps > partiview2.ps