Use https for gnu.org links

Mostly already done, but there were some stragglers.

doc/src/sgml/installation.sgml

@@ -239,7 +239,7 @@ su - postgres
       class="osname">Linux</systemitem>, <systemitem class="osname">NetBSD</systemitem>,
       <systemitem class="osname">Solaris</systemitem>), for other systems you
       can download an add-on package from <ulink
-      url="http://www.gnu.org/software/gettext/"></ulink>.
+      url="https://www.gnu.org/software/gettext/"></ulink>.
       If you are using the <application>Gettext</application> implementation in
       the <acronym>GNU</acronym> C library then you will additionally
       need the <productname>GNU Gettext</productname> package for some

src/include/c.h

@@ -1132,7 +1132,8 @@ typedef union PGAlignedXLogBlock
  *	access to the original string and translated string, and for cases where
  *	immediate translation is not possible, like when initializing global
  *	variables.
- *		http://www.gnu.org/software/autoconf/manual/gettext/Special-cases.html
+ *
+ *	https://www.gnu.org/software/gettext/manual/html_node/Special-cases.html
  */
 #define gettext_noop(x) (x)
 

src/include/port/atomics/generic-gcc.h

@@ -10,9 +10,9 @@
  *
  * Documentation:
  * * Legacy __sync Built-in Functions for Atomic Memory Access
- *   http://gcc.gnu.org/onlinedocs/gcc-4.8.2/gcc/_005f_005fsync-Builtins.html
+ *   https://gcc.gnu.org/onlinedocs/gcc-4.8.2/gcc/_005f_005fsync-Builtins.html
  * * Built-in functions for memory model aware atomic operations
- *   http://gcc.gnu.org/onlinedocs/gcc-4.8.2/gcc/_005f_005fatomic-Builtins.html
+ *   https://gcc.gnu.org/onlinedocs/gcc-4.8.2/gcc/_005f_005fatomic-Builtins.html
  *
  * src/include/port/atomics/generic-gcc.h
  *

src/interfaces/ecpg/Makefile

@@ -5,7 +5,7 @@ include $(top_builddir)/src/Makefile.global
 SUBDIRS = include pgtypeslib ecpglib compatlib preproc
 
 # Suppress parallel build of subdirectories to avoid a bug in GNU make 3.82, cf
-# http://savannah.gnu.org/bugs/?30653
+# https://savannah.gnu.org/bugs/?30653
 # https://bugzilla.redhat.com/show_bug.cgi?id=835424
 # (There are some other parallelism bugs in the subdirectory makefiles
 # themselves, but there's little point in fixing them as long as we have

src/tools/RELEASE_CHANGES

@@ -73,7 +73,7 @@ but there may be reasons to do them at other times as well.
   to lower numbers, using renumber_oids.pl (see notes in bki.sgml)
 
 * Update config.guess and config.sub
-  (from http://savannah.gnu.org/projects/config)
+  (from https://savannah.gnu.org/projects/config)
 
 * Update inet/cidr data types with newest Bind patches