Prefer https: URLs

In Gnulib, Emacs, etc. we are changing ftp: and http: URLs to use
https:, to discourage man-in-the-middle attacks when downloading
software. The attached patch propagates these changes upstream to
Automake.  This patch does not affect files that Automake is
downstream of, which I'll patch separately.

Althouth the resources are not secret, plain HTTP is vulnerable to
malicious routers that tamper with responses from GNU servers,
and this sort of thing is all too common when people in some other
countries browse US-based websites. See, for example:

Aceto G, Botta A, Pescapé A, Awan MF, Ahmad T, Qaisar
S. Analyzing internet censorship in Pakistan. RTSI
2016. https://dx.doi.org/10.1109/RTSI.2016.7740626

HTTPS is not a complete solution here, but it can be a significant
help. The GNU project regularly serves up code to users, so we should
take some care here.

40 files changed, 45 insertions, 46 deletions

diff --git a/lib/am/check.am b/lib/am/check.am
index ff174191d..9b05fc2c4 100644
--- a/lib/am/check.am
+++ b/lib/am/check.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 am__tty_colors_dummy = \
   mgn= red= grn= lgn= blu= brg= std=; \
@@ -390,7 +390,7 @@ $(TEST_SUITE_LOG): $(TEST_LOGS)
 ## Be sure to exit with the proper exit status.  The use of "exit 1" below
 ## is required to work around a FreeBSD make bug (present only when running
 ## in concurrent mode).  See automake bug#9245:
-##  <http://debbugs.gnu.org/cgi/bugreport.cgi?bug=9245>
+##  <https://debbugs.gnu.org/cgi/bugreport.cgi?bug=9245>
 ## and FreeBSD PR bin/159730:
 ##  <http://www.freebsd.org/cgi/query-pr.cgi?pr=159730>.
 	$$success || exit 1
diff --git a/lib/am/check2.am b/lib/am/check2.am
index 1a1c34fe8..fbf4c7786 100644
--- a/lib/am/check2.am
+++ b/lib/am/check2.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 if %?FIRST%
 ## When BSD make is run in parallel mode, it apparently strips any
diff --git a/lib/am/clean-hdr.am b/lib/am/clean-hdr.am
index 9a12b6915..1de69a28b 100644
--- a/lib/am/clean-hdr.am
+++ b/lib/am/clean-hdr.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 .PHONY: distclean-hdr
 distclean-am: distclean-hdr
diff --git a/lib/am/clean.am b/lib/am/clean.am
index 59d9544b0..e4a7fdb25 100644
--- a/lib/am/clean.am
+++ b/lib/am/clean.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 ## We must test each macro because it might be empty, and an empty "rm
 ## -rf" command looks disturbing.  Also, the Solaris 2.4 "rm" will
diff --git a/lib/am/compile.am b/lib/am/compile.am
index c45b04f62..c92e72d4f 100644
--- a/lib/am/compile.am
+++ b/lib/am/compile.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 DEFAULT_INCLUDES = %DEFAULT_INCLUDES%
 
diff --git a/lib/am/configure.am b/lib/am/configure.am
index ec0b293ad..6f0c50883 100644
--- a/lib/am/configure.am
+++ b/lib/am/configure.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 
 ## This dummy rule is called from subdirectories whenever one of the
diff --git a/lib/am/data.am b/lib/am/data.am
index 6facf0acd..34b582f46 100644
--- a/lib/am/data.am
+++ b/lib/am/data.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 if %?INSTALL%
 include inst-vars.am
diff --git a/lib/am/dejagnu.am b/lib/am/dejagnu.am
index 04e97e2b1..4aa8f9cc2 100644
--- a/lib/am/dejagnu.am
+++ b/lib/am/dejagnu.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 ## Name of tool to use.  Default is the same as the package.
 DEJATOOL = $(PACKAGE)
diff --git a/lib/am/depend.am b/lib/am/depend.am
index 8ce0cd4c7..1538036c5 100644
--- a/lib/am/depend.am
+++ b/lib/am/depend.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 am__mv = mv -f
 
diff --git a/lib/am/depend2.am b/lib/am/depend2.am
index e7a90bf86..45dd88c5e 100644
--- a/lib/am/depend2.am
+++ b/lib/am/depend2.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 ## This file is read several times:
 ## - once per *extension* (not per language) for generic compilation rules
diff --git a/lib/am/distdir.am b/lib/am/distdir.am
index 200bdba66..653966f0e 100644
--- a/lib/am/distdir.am
+++ b/lib/am/distdir.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 DIST_COMMON += $(am__DIST_COMMON)
 DISTFILES = $(DIST_COMMON) $(DIST_SOURCES) $(TEXINFOS) $(EXTRA_DIST)
diff --git a/lib/am/footer.am b/lib/am/footer.am
index 07f538805..7291df1c8 100644
--- a/lib/am/footer.am
+++ b/lib/am/footer.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 # Tell versions [3.59,3.63) of GNU make to not export all variables.
 # Otherwise a system limit (for SysV at least) may be exceeded.
diff --git a/lib/am/header-vars.am b/lib/am/header-vars.am
index 309468491..10066b397 100644
--- a/lib/am/header-vars.am
+++ b/lib/am/header-vars.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 VPATH = @srcdir@
 
diff --git a/lib/am/header.am b/lib/am/header.am
index f2a0e9559..d4dba1285 100644
--- a/lib/am/header.am
+++ b/lib/am/header.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 
 ## Exactly the same as data.am.
diff --git a/lib/am/inst-vars.am b/lib/am/inst-vars.am
index 5581f679c..2f2824522 100644
--- a/lib/am/inst-vars.am
+++ b/lib/am/inst-vars.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 if %?FIRST%
 
diff --git a/lib/am/install.am b/lib/am/install.am
index 5adcb52c0..6ba28e732 100644
--- a/lib/am/install.am
+++ b/lib/am/install.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 ## ----------------------------------------- ##
 ## installdirs -- Creating the installdirs.  ##
diff --git a/lib/am/java.am b/lib/am/java.am
index 6398f0e6d..4f78e533d 100644
--- a/lib/am/java.am
+++ b/lib/am/java.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 
 ## ---------- ##
diff --git a/lib/am/lang-compile.am b/lib/am/lang-compile.am
index 545e0cf4e..b6c5434b5 100644
--- a/lib/am/lang-compile.am
+++ b/lib/am/lang-compile.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 ## This file is read once per *language*, not per extension.
 
diff --git a/lib/am/lex.am b/lib/am/lex.am
index c28674d11..b57bc5c90 100644
--- a/lib/am/lex.am
+++ b/lib/am/lex.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 ## See the comment about am__skipyacc in yacc.am.
 if %?MAINTAINER-MODE%
diff --git a/lib/am/library.am b/lib/am/library.am
index 8bb1390ae..19a7f1a01 100644
--- a/lib/am/library.am
+++ b/lib/am/library.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 %LIBRARY%: $(%XLIBRARY%_OBJECTS) $(%XLIBRARY%_DEPENDENCIES) $(EXTRA_%XLIBRARY%_DEPENDENCIES) %DIRSTAMP%
 	%SILENT%-rm -f %LIBRARY%
diff --git a/lib/am/libs.am b/lib/am/libs.am
index 77f91787b..377fdc552 100644
--- a/lib/am/libs.am
+++ b/lib/am/libs.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 if %?INSTALL%
 include inst-vars.am
diff --git a/lib/am/libtool.am b/lib/am/libtool.am
index a2f1ae55e..9b882d918 100644
--- a/lib/am/libtool.am
+++ b/lib/am/libtool.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 .PHONY: mostlyclean-libtool clean-libtool distclean-libtool
 mostlyclean-am: mostlyclean-libtool
diff --git a/lib/am/lisp.am b/lib/am/lisp.am
index 8085e3f0d..881bf3457 100644
--- a/lib/am/lisp.am
+++ b/lib/am/lisp.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 if %?INSTALL%
 include inst-vars.am
diff --git a/lib/am/local.mk b/lib/am/local.mk
index 270bb7347..3c2d9ba39 100644
--- a/lib/am/local.mk
+++ b/lib/am/local.mk
@@ -13,7 +13,7 @@
 ## GNU General Public License for more details.
 ##
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 ## --------------------- ##
 ##  Makefile fragments.  ##
diff --git a/lib/am/ltlib.am b/lib/am/ltlib.am
index 45f020327..b99f0bf0a 100644
--- a/lib/am/ltlib.am
+++ b/lib/am/ltlib.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 if %?INSTALL%
 include inst-vars.am
diff --git a/lib/am/ltlibrary.am b/lib/am/ltlibrary.am
index ce4c1faf5..a7a2c380b 100644
--- a/lib/am/ltlibrary.am
+++ b/lib/am/ltlibrary.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 %LTLIBRARY%: $(%XLTLIBRARY%_OBJECTS) $(%XLTLIBRARY%_DEPENDENCIES) $(EXTRA_%XLTLIBRARY%_DEPENDENCIES) %DIRSTAMP%
 	%VERBOSE%$(%XLINK%) %RPATH% $(%XLTLIBRARY%_OBJECTS) $(%XLTLIBRARY%_LIBADD) $(LIBS)
diff --git a/lib/am/mans-vars.am b/lib/am/mans-vars.am
index 24b9e20c0..3b0f49dff 100644
--- a/lib/am/mans-vars.am
+++ b/lib/am/mans-vars.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 NROFF = nroff
 ## We don't really need this, but we use it in case we ever want to
diff --git a/lib/am/mans.am b/lib/am/mans.am
index 85c180821..59d9dd4a2 100644
--- a/lib/am/mans.am
+++ b/lib/am/mans.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 include inst-vars.am
 man%SECTION%dir = $(mandir)/man%SECTION%
diff --git a/lib/am/program.am b/lib/am/program.am
index ba1bbb553..d2fe0e0a5 100644
--- a/lib/am/program.am
+++ b/lib/am/program.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 %PROGRAM%%EXEEXT%: $(%XPROGRAM%_OBJECTS) $(%XPROGRAM%_DEPENDENCIES) $(EXTRA_%XPROGRAM%_DEPENDENCIES) %DIRSTAMP%
 ## Remove program before linking.  Otherwise the link will fail if the
diff --git a/lib/am/progs.am b/lib/am/progs.am
index 4c94b5b19..cbea73012 100644
--- a/lib/am/progs.am
+++ b/lib/am/progs.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 ## ------------ ##
 ## Installing.  ##
diff --git a/lib/am/python.am b/lib/am/python.am
index e20f602cf..5c438d51d 100644
--- a/lib/am/python.am
+++ b/lib/am/python.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 if %?INSTALL%
 include inst-vars.am
diff --git a/lib/am/remake-hdr.am b/lib/am/remake-hdr.am
index dd26e4ef5..52510abdc 100644
--- a/lib/am/remake-hdr.am
+++ b/lib/am/remake-hdr.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 %CONFIG_H%: %STAMP%
 ## Recover from removal of CONFIG_HEADER.
diff --git a/lib/am/scripts.am b/lib/am/scripts.am
index 5422392af..6a9a23e56 100644
--- a/lib/am/scripts.am
+++ b/lib/am/scripts.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 if %?INSTALL%
 include inst-vars.am
diff --git a/lib/am/subdirs.am b/lib/am/subdirs.am
index 84102493c..db681ba73 100644
--- a/lib/am/subdirs.am
+++ b/lib/am/subdirs.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 RECURSIVE_TARGETS += all-recursive check-recursive installcheck-recursive
 RECURSIVE_CLEAN_TARGETS = mostlyclean-recursive clean-recursive	\
@@ -73,4 +73,3 @@ mostlyclean: mostlyclean-recursive
 clean: clean-recursive
 distclean: distclean-recursive
 maintainer-clean: maintainer-clean-recursive
-
diff --git a/lib/am/tags.am b/lib/am/tags.am
index 7a93cde93..151402e23 100644
--- a/lib/am/tags.am
+++ b/lib/am/tags.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 # Read a list of newline-separated strings from the standard input,
 # and print each of them once, without duplicates.  Input order is
diff --git a/lib/am/texi-vers.am b/lib/am/texi-vers.am
index 1806c3eac..841f7d7cb 100644
--- a/lib/am/texi-vers.am
+++ b/lib/am/texi-vers.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 DIST_COMMON += %VTEXI% %STAMPVTI%
 
diff --git a/lib/am/texibuild.am b/lib/am/texibuild.am
index 6c9265bd2..e2d1b669f 100644
--- a/lib/am/texibuild.am
+++ b/lib/am/texibuild.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 
 ?GENERIC_INFO?%SOURCE_SUFFIX%%DEST_SUFFIX%:
@@ -73,7 +73,7 @@ INFO_DEPS += %DEST_INFO_PREFIX%%DEST_SUFFIX%
 ## each file (and distinct from that of the corresponding PDF file) to
 ## avoid hitting a Texinfop bug that could cause low-probability racy
 ## failure when doing parallel builds; see:
-## http://lists.gnu.org/archive/html/automake-patches/2012-06/msg00073.html
+## https://lists.gnu.org/archive/html/automake-patches/2012-06/msg00073.html
 	$(TEXI2DVI) %TEXIQUIET% --build-dir=$(@:.dvi=.t2d) -o $@ %TEXIDEVNULL% \
 ?GENERIC?	%SOURCE%
 ?!GENERIC?	`test -f '%SOURCE%' || echo '$(srcdir)/'`%SOURCE%
@@ -92,7 +92,7 @@ INFO_DEPS += %DEST_INFO_PREFIX%%DEST_SUFFIX%
 ## each file (and distinct from that of the corresponding DVI file) to
 ## avoid hitting a Texinfop bug that could cause low-probability racy
 ## failure when doing parallel builds; see:
-## http://lists.gnu.org/archive/html/automake-patches/2012-06/msg00073.html
+## https://lists.gnu.org/archive/html/automake-patches/2012-06/msg00073.html
 	$(TEXI2PDF) %TEXIQUIET% --build-dir=$(@:.pdf=.t2p) -o $@ %TEXIDEVNULL% \
 ?GENERIC?	%SOURCE%
 ?!GENERIC?	`test -f '%SOURCE%' || echo '$(srcdir)/'`%SOURCE%
diff --git a/lib/am/texinfos.am b/lib/am/texinfos.am
index 2997a16b3..a2a21e667 100644
--- a/lib/am/texinfos.am
+++ b/lib/am/texinfos.am
@@ -13,7 +13,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 ## ----------- ##
 ## Variables.  ##
@@ -159,9 +159,9 @@ install-html-am: $(HTMLS)
 	  $(am__strip_dir) \
 ## This indirection is required to work around a bug of the Solaris 10
 ## shell /usr/xpg4/bin/sh.  The description of the bug can be found at
-## <http://lists.gnu.org/archive/html/bug-autoconf/2011-11/msg00005.html>
+## <https://lists.gnu.org/archive/html/bug-autoconf/2011-11/msg00005.html>
 ## and the report of the original failure can be found at automake
-## bug#10026 <http://debbugs.gnu.org/cgi/bugreport.cgi?bug=10026#23>
+## bug#10026 <https://debbugs.gnu.org/cgi/bugreport.cgi?bug=10026#23>
 	  d2=$$d$$p; \
 	  if test -d "$$d2"; then \
 	    echo " $(MKDIR_P) '$(DESTDIR)$(htmldir)/$$f'"; \
diff --git a/lib/am/vala.am b/lib/am/vala.am
index 836e12e87..f20b00c2c 100644
--- a/lib/am/vala.am
+++ b/lib/am/vala.am
@@ -12,6 +12,6 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 ## There is no rule here.  :-)
diff --git a/lib/am/yacc.am b/lib/am/yacc.am
index be1bf77a7..28f05d2de 100644
--- a/lib/am/yacc.am
+++ b/lib/am/yacc.am
@@ -12,7 +12,7 @@
 ## GNU General Public License for more details.
 
 ## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+## along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 ## We want to disable the Yacc rebuild rule when
 ##   1. AM_MAINTAINER_MODE is used, and