Make INSTALL makefile rule more robust

With the previous rule, if pandoc was missing, a zero-length output
file would be created without an error from make.  To improve that,
write the rule as two separate commands without a pipe.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>

diff --git a/doc/src/sgml/Makefile b/doc/src/sgml/Makefile
index 93b0b60cdb64b4c116c584c9a0b5c1a3742bde44..8326c7c67364ca5b4a530d5a73732bc659f77443 100644 (file)
--- a/doc/src/sgml/Makefile
+++ b/doc/src/sgml/Makefile
@@ -103,7 +103,9 @@ ICONV = iconv
 PANDOC = pandoc
 
 INSTALL: % : %.html
-   $(PANDOC) $< -t plain | $(ICONV) -f utf8 -t us-ascii//TRANSLIT > $@
+   $(PANDOC) -t plain -o $@.tmp $<
+   $(ICONV) -f utf8 -t us-ascii//TRANSLIT $@.tmp > $@
+   rm $@.tmp
 
 INSTALL.html: %.html : stylesheet-text.xsl %.xml
    $(XMLLINT) --noout --valid $*.xml