Fix the makefiles to fail cleanly if Perl is needed but not present. This

used to work as intended, but got broken some time ago (a quoted empty string
is not an empty string), and got broken some more by the changes to generate
ecpg's preproc.y automatically.  Given all the unprotected uses of $(PERL)
elsewhere, it seems best to make use of the $(missing) script rather than
trying to ensure each such use is protected individually.  Also fix various
bits of documentation that omitted to mention Perl as a requirement for
building from a CVS pull.  Per a complaint from Robert Haas.

6 files changed, 44 insertions, 13 deletions

diff --git a/README.CVS b/README.CVS
index 37daaf6bc3..4eb8377a50 100644
--- a/README.CVS
+++ b/README.CVS
@@ -8,7 +8,7 @@ If you are using CVS, you can view the most recent install instructions at:
 and the current release notes at:
 	http://developer.postgresql.org/docs/postgres/release.html
 
-Users compiling from CVS will also need compatible versions of Bison and
-Flex, as discussed in the install documentation.  Bison and Flex are not
+Users compiling from CVS will also need compatible versions of Bison, Flex,
+and Perl, as discussed in the install documentation.  These programs are not
 needed when using a tarball, since the files they are needed to build are
-already present in the tarball.
+already present in the tarball.  (On Windows, however, you need Perl anyway.)
diff --git a/config/missing b/config/missing
index 1c8bd8af96..896a33c200 100755
--- a/config/missing
+++ b/config/missing
@@ -17,7 +17,7 @@ case $1 in
 WARNING: \`$1' is missing on your system. You should only need it
 if you changed the file \`$input'; these changes will not take effect.
 You can get $1 from a GNU mirror site.
-***"
+***" >&2
             echo "touch $output"
             touch "$output"
             exit 0
@@ -28,8 +28,27 @@ ERROR: \`$1' is missing on your system. It is needed to create the
 file \`$output'. You can either get $1 from a GNU mirror site
 or download an official distribution of PostgreSQL, which contains
 pre-packaged $1 output.
-***"
+***" >&2
             exit 1
         fi
         ;;
+
+    perl)
+        # `missing perl'
+        echo "\
+***
+ERROR: Perl is missing on your system. It is needed unless you are building
+from an unmodified official distribution of PostgreSQL.
+***" >&2
+        exit 1
+        ;;
+
+    *)
+        # `missing something-or-other'
+        echo "\
+***
+ERROR: \`$1' is missing on your system.
+***" >&2
+        exit 1
+        ;;
 esac
diff --git a/doc/src/sgml/cvs.sgml b/doc/src/sgml/cvs.sgml
index 0b19b00e5d..003e4e7760 100644
--- a/doc/src/sgml/cvs.sgml
+++ b/doc/src/sgml/cvs.sgml
@@ -171,6 +171,7 @@ cvs update
    pull requires reasonably up-to-date versions of <application>bison</>
    and <application>flex</>, which are not needed to build from a distribution
    tarball because the files made with them are pre-built in a tarball.
+   You will need Perl as well.
    Otherwise the tool requirements are the same as building from source.
   </para>
  </sect1>
diff --git a/doc/src/sgml/installation.sgml b/doc/src/sgml/installation.sgml
index 2c053e4147..c058141079 100644
--- a/doc/src/sgml/installation.sgml
+++ b/doc/src/sgml/installation.sgml
@@ -294,13 +294,25 @@ su - postgres
       </indexterm>
 
       GNU <application>Flex</> and <application>Bison</>
-      are needed to build a CVS checkout or if you changed the actual
+      are needed to build from a CVS checkout, or if you changed the actual
       scanner and parser definition files. If you need them, be sure
       to get <application>Flex</> 2.5.4 or later and
       <application>Bison</> 1.875 or later. Other <application>lex</>
       and <application>yacc</> programs cannot be used.
      </para>
     </listitem>
+    <listitem>
+     <para>
+      <indexterm>
+       <primary>perl</primary>
+      </indexterm>
+
+      <application>Perl</> is also needed to build from a CVS checkout,
+      or if you changed the input files for any of the build steps that
+      use Perl scripts.  If building on Windows you will need
+      <application>Perl</> in any case.
+     </para>
+    </listitem>
    </itemizedlist>
   </para>
 
diff --git a/src/Makefile.global.in b/src/Makefile.global.in
index 829ce7218d..6244e8ac8c 100644
--- a/src/Makefile.global.in
+++ b/src/Makefile.global.in
@@ -248,8 +248,12 @@ X = @EXEEXT@
 
 # Perl 
 
-# quoted for pathname with spaces
-PERL			= "@PERL@"
+ifneq (@PERL@,)
+    # quoted to protect pathname with spaces
+    PERL		= "@PERL@"
+else
+    PERL		= $(missing) perl
+endif
 perl_archlibexp		= @perl_archlibexp@
 perl_privlibexp		= @perl_privlibexp@
 perl_useshrplib		= @perl_useshrplib@
diff --git a/src/bin/psql/Makefile b/src/bin/psql/Makefile
index cc7d42ec4e..1d82caf8d0 100644
--- a/src/bin/psql/Makefile
+++ b/src/bin/psql/Makefile
@@ -40,13 +40,8 @@ dumputils.c keywords.c: % : $(top_srcdir)/src/bin/pg_dump/%
 kwlookup.c: % : $(top_srcdir)/src/backend/parser/%
 	rm -f $@ && $(LN_S) $< .
 
-ifdef PERL
 $(srcdir)/sql_help.h: create_help.pl $(wildcard $(REFDOCDIR)/*.sgml)
 	$(PERL) $< $(REFDOCDIR) $@
-else
-$(srcdir)/sql_help.h:
-	@echo "*** Perl is needed to build psql help."
-endif
 
 $(srcdir)/psqlscan.c: psqlscan.l
 ifdef FLEX