Quote 'like this' in top-level files

* CONTRIBUTE, INSTALL, Makefile.in, README, configure.ac, make-dist:
Prefer to single-quote 'like this' (instead of the older style
`like this').
* configure.ac: Fix some space-before-tab problems that 'git commit'
complained about.

CONTRIBUTE

@@ -146,7 +146,7 @@ The general format is as follows.
   a top-level ChangeLog file manually, and update it with 'C-x 4 a' as
   usual.  Do not register the ChangeLog file under git; instead, use
   'C-c C-a' to insert its contents into into your *vc-log* buffer.
-  Or if `log-edit-hook' includes `log-edit-insert-changelog' (which it
+  Or if 'log-edit-hook' includes 'log-edit-insert-changelog' (which it
   does by default), they will be filled in for you automatically.
 
 - Alternatively, you can use the vc-dwim command to maintain commit
@@ -236,7 +236,7 @@ the entry with "+++". Otherwise do not mark it.
 
 Please see (info "(elisp)Documentation Tips") or
 https://www.gnu.org/software/emacs/manual/html_node/elisp/Documentation-Tips.html
-for more specific tips on Emacs's doc style.  Use `checkdoc' to check
+for more specific tips on Emacs's doc style.  Use 'checkdoc' to check
 for documentation errors before submitting a patch.
 
 ** Test your changes.

Makefile.in

@@ -30,13 +30,13 @@
 #      by building, but normally aren't because the distribution comes
 #      with them.
 #
-#      Delete `.dvi' files here if they are not part of the distribution.
+#      Delete '.dvi' files here if they are not part of the distribution.
 #
 # make distclean
 #      Delete all files from the current directory that are created by
 #      configuring or building the program.  If you have unpacked the
 #      source and built the program without creating any other files,
-#      `make distclean' should leave only the files that were in the
+#      'make distclean' should leave only the files that were in the
 #      distribution.
 #
 # make maintainer-clean
@@ -67,7 +67,7 @@ CDPATH=
 # If Make doesn't predefine MAKE, set it here.
 @SET_MAKE@
 
-# ==================== Things `configure' Might Edit ====================
+# ==================== Things 'configure' Might Edit ====================
 
 cache_file = @cache_file@
 CONFIGURE_FLAGS = --cache-file=$(cache_file)
@@ -84,11 +84,11 @@ EXEEXT=@EXEEXT@
 ### to install files in.
 
 ### This should be the number of the Emacs version we're building,
-### like `18.59' or `19.0'.
+### like '24.5' or '25.0.50'.
 version=@version@
 
 ### This should be the name of the configuration we're building Emacs
-### for, like `mips-dec-ultrix' or `sparc-sun-sunos'.
+### for, like 'x86_64-unknown-linux-gnu' or 'powerpc-ibm-aix7.1.2.0'.
 configuration=@configuration@
 
 ### The nt/ subdirectory gets built only for MinGW
@@ -122,7 +122,7 @@ ns_self_contained=@ns_self_contained@
 # not need to change them.  This defaults to /usr/local.
 prefix=@prefix@
 
-# Like `prefix', but used for architecture-specific files.
+# Like 'prefix', but used for architecture-specific files.
 exec_prefix=@exec_prefix@
 
 # Where to install Emacs and other binaries that people will want to
@@ -171,7 +171,7 @@ bitmapdir=@bitmapdir@
 # Where to find the source code.  The source code for Emacs's C kernel is
 # expected to be in ${srcdir}/src, and the source code for Emacs's
 # utility programs is expected to be in ${srcdir}/lib-src.  This is
-# set by the configure script's `--srcdir' option.
+# set by the configure script's '--srcdir' option.
 
 # We use $(srcdir) explicitly in dependencies so as not to depend on VPATH.
 srcdir=@srcdir@
@@ -316,7 +316,7 @@ etc-emacsver:
 
 removenullpaths=sed -e 's/^:*//' -e 's/:*$$//g' -e 's/::*/:/g'
 
-# Generate epaths.h from epaths.in.  This target is invoked by `configure'.
+# Generate epaths.h from epaths.in.  This target is invoked by 'configure'.
 # See comments in configure.ac for why it is done this way, as opposed
 # to just letting configure generate epaths.h from epaths.in in a
 # similar way to how Makefile is made from Makefile.in.
@@ -350,7 +350,7 @@ epaths-force:
 # The w32 build needs a slightly different editing, and it uses
 # nt/epaths.nt as the template.
 #
-# Use the value of ${locallisppath} supplied by `configure',
+# Use the value of ${locallisppath} supplied by 'configure',
 # to support the --enable-locallisppath argument.
 #
 # In this case, the paths written to 'src/epaths.h' must be in native
@@ -377,10 +377,10 @@ lib-src src: $(NTDIR) lib
 
 src: lib-src
 
-# We need to build `emacs' in `src' to compile the *.elc files in `lisp'.
+# We need to build 'emacs' in 'src' to compile the *.elc files in 'lisp'.
 lisp: src
 
-# These targets should be "${SUBDIR} without `src'".
+# These targets should be "${SUBDIR} without 'src'".
 lib lib-src lisp nt: Makefile
 	$(MAKE) -C $@ all
 
@@ -733,8 +733,8 @@ install-etc:
 install-strip:
 	$(MAKE) INSTALL_STRIP=-s install
 
-### Delete all the installed files that the `install' target would
-### create (but not the noninstalled files such as `make all' would create).
+### Delete all the installed files that the 'install' target would
+### create (but not the noninstalled files such as 'make all' would create).
 ###
 ### Don't delete the lisp and etc directories if they're in the source tree.
 uninstall: uninstall-$(NTDIR) uninstall-doc
@@ -803,10 +803,10 @@ $(1)_$(2):
 	$$(MAKE) -C $(1) $(2)
 endef
 
-### `mostlyclean'
-###      Like `clean', but may refrain from deleting a few files that people
-###      normally don't want to recompile.  For example, the `mostlyclean'
-###      target for GCC does not delete `libgcc.a', because recompiling it
+### 'mostlyclean'
+###      Like 'clean', but may refrain from deleting a few files that people
+###      normally don't want to recompile.  For example, the 'mostlyclean'
+###      target for GCC does not delete 'libgcc.a', because recompiling it
 ###      is rarely necessary and takes a lot of time.
 mostlyclean_dirs = src oldXMenu lwlib lib lib-src nt doc/emacs doc/misc \
   doc/lispref doc/lispintro
@@ -818,14 +818,14 @@ mostlyclean: $(mostlyclean_dirs:=_mostlyclean)
 	  [ ! -d $$dir ] || $(MAKE) -C $$dir mostlyclean; \
 	done
 
-### `clean'
+### 'clean'
 ###      Delete all files from the current directory that are normally
 ###      created by building the program.  Don't delete the files that
 ###      record the configuration.  Also preserve files that could be made
 ###      by building, but normally aren't because the distribution comes
 ###      with them.
 ###
-###      Delete `.dvi' files here if they are not part of the distribution.
+###      Delete '.dvi' files here if they are not part of the distribution.
 clean_dirs = $(mostlyclean_dirs) nextstep
 
 $(foreach dir,$(clean_dirs),$(eval $(call submake_template,$(dir),clean)))
@@ -837,16 +837,16 @@ clean: $(clean_dirs:=_clean)
 	-rm -f *.tmp etc/*.tmp*
 	-rm -rf info-dir.*
 
-### `bootclean'
+### 'bootclean'
 ###      Delete all files that need to be remade for a clean bootstrap.
 top_bootclean=\
 	rm -f config.cache config.log ${srcdir}/doc/man/emacs.1
 
-### `distclean'
+### 'distclean'
 ###      Delete all files from the current directory that are created by
 ###      configuring or building the program.  If you have unpacked the
 ###      source and built the program without creating any other files,
-###      `make distclean' should leave only the files that were in the
+###      'make distclean' should leave only the files that were in the
 ###      distribution.
 top_distclean=\
 	${top_bootclean}; \
@@ -862,8 +862,8 @@ distclean: $(distclean_dirs:=_distclean)
 	done
 	${top_distclean}
 
-### `bootstrap-clean'
-###      Delete everything that can be reconstructed by `make' and that
+### 'bootstrap-clean'
+###      Delete everything that can be reconstructed by 'make' and that
 ###      needs to be deleted in order to force a bootstrap from a clean state.
 $(foreach dir,$(distclean_dirs),$(eval $(call submake_template,$(dir),bootstrap-clean)))
 
@@ -876,16 +876,16 @@ bootstrap-clean: $(distclean_dirs:=_bootstrap-clean)
 	rm -f ${srcdir}/etc/refcards/emacsver.tex
 	${top_bootclean}
 
-### `maintainer-clean'
+### 'maintainer-clean'
 ###      Delete everything from the current directory that can be
 ###      reconstructed with this Makefile.  This typically includes
 ###      everything deleted by distclean, plus more: C source files
 ###      produced by Bison, tags tables, info files, and so on.
 ###
-###      One exception, however: `make maintainer-clean' should not delete
-###      `configure' even if `configure' can be remade using a rule in the
-###      Makefile.  More generally, `make maintainer-clean' should not delete
-###      anything that needs to exist in order to run `configure' and then
+###      One exception, however: 'make maintainer-clean' should not delete
+###      'configure' even if 'configure' can be remade using a rule in the
+###      Makefile.  More generally, 'make maintainer-clean' should not delete
+###      anything that needs to exist in order to run 'configure' and then
 ###      begin to build the program.
 top_maintainer_clean=\
 	${top_distclean}; \

README

@@ -22,71 +22,71 @@ in code we don't use often.  Please send bug reports to the mailing
 list bug-gnu-emacs@gnu.org.  If possible, use M-x report-emacs-bug.
 
 See the "Bugs" section of the Emacs manual for more information on how
-to report bugs.  (The file `BUGS' in this directory explains how you
+to report bugs.  (The file 'BUGS' in this directory explains how you
 can find and read that section using the Info files that come with
 Emacs.)  For a list of mailing lists related to Emacs, see
 <http://savannah.gnu.org/mail/?group=emacs>.  For the complete
 list of GNU mailing lists, see <http://lists.gnu.org/>.
 
-The `etc' subdirectory contains several other files, named in capital
+The 'etc' subdirectory contains several other files, named in capital
 letters, which you might consider looking at when installing GNU
 Emacs.
 
-The file `configure' is a shell script to acclimate Emacs to the
+The file 'configure' is a shell script to acclimate Emacs to the
 oddities of your processor and operating system.  It creates the file
-`Makefile' (a script for the `make' program), which automates the
+'Makefile' (a script for the 'make' program), which automates the
 process of building and installing Emacs.  See INSTALL for more
 detailed information.
 
-The file `configure.ac' is the input used by the autoconf program to
-construct the `configure' script.
+The file 'configure.ac' is the input used by the autoconf program to
+construct the 'configure' script.
 
-The shell script `autogen.sh' generates 'configure' and other files by
+The shell script 'autogen.sh' generates 'configure' and other files by
 running the GNU build tools autoconf and automake, which in turn use
 GNU m4 and Perl.  If you want to use it, you will need to install
 recent versions of these build tools.  This should be needed only if
-you edit files like `configure.ac' that specify Emacs's autobuild
+you edit files like 'configure.ac' that specify Emacs's autobuild
 procedure.
 
-The file `Makefile.in' is a template used by `configure' to create
-`Makefile'.
+The file 'Makefile.in' is a template used by 'configure' to create
+'Makefile'.
 
-The file `make-dist' is a shell script to build a distribution tar
+The file 'make-dist' is a shell script to build a distribution tar
 file from the current Emacs tree, containing only those files
 appropriate for distribution.  If you make extensive changes to Emacs,
 this script will help you distribute your version to others.
 
 There are several subdirectories:
 
-`src'       holds the C code for Emacs (the Emacs Lisp interpreter and
+'src'       holds the C code for Emacs (the Emacs Lisp interpreter and
             its primitives, the redisplay code, and some basic editing
             functions).
-`lisp'      holds the Emacs Lisp code for Emacs (most everything else).
-`leim'      holds the original source files for the generated files
+'lisp'      holds the Emacs Lisp code for Emacs (most everything else).
+'leim'      holds the original source files for the generated files
             in lisp/leim.  These form the library of Emacs input methods,
             required to type international characters that can't be
             directly produced by your keyboard.
-`lib'       holds source code for libraries used by Emacs and its utilities
-`lib-src'   holds the source code for some utility programs for use by or
+'lib'       holds source code for libraries used by Emacs and its utilities
+'lib-src'   holds the source code for some utility programs for use by or
             with Emacs, like movemail and etags.
-`etc'       holds miscellaneous architecture-independent data files Emacs
+'etc'       holds miscellaneous architecture-independent data files Emacs
             uses, like the tutorial text and tool bar images.
-            The contents of the `lisp', `leim', `info', and `doc'
+            The contents of the 'lisp', 'leim', 'info', and 'doc'
             subdirectories are architecture-independent too.
-`info'      holds the Info documentation tree for Emacs.
-`doc/emacs' holds the source code for the Emacs Manual.  If you modify the
-            manual sources, you will need the `makeinfo' program to produce
-            an updated manual.  `makeinfo' is part of the GNU Texinfo
+'info'      holds the Info documentation tree for Emacs.
+'doc/emacs' holds the source code for the Emacs Manual.  If you modify the
+            manual sources, you will need the 'makeinfo' program to produce
+            an updated manual.  'makeinfo' is part of the GNU Texinfo
             package; you need a suitably recent version of Texinfo.
-`doc/lispref'   holds the source code for the Emacs Lisp reference manual.
-`doc/lispintro' holds the source code for the Introduction to Programming
+'doc/lispref'   holds the source code for the Emacs Lisp reference manual.
+'doc/lispintro' holds the source code for the Introduction to Programming
                 in Emacs Lisp manual.
-`msdos'     holds configuration files for compiling Emacs under MS-DOS.
-`nextstep'  holds instructions and some other files for compiling the
+'msdos'     holds configuration files for compiling Emacs under MS-DOS.
+'nextstep'  holds instructions and some other files for compiling the
             Nextstep port of Emacs, for GNUstep and Mac OS X Cocoa.
-`nt'        holds various command files and documentation files that pertain
+'nt'        holds various command files and documentation files that pertain
             to building and running Emacs on Windows 9X/ME/NT/2000/XP.
-`test'      holds tests for various aspects of Emacs's functionality.
+'test'      holds tests for various aspects of Emacs's functionality.
 
    Building Emacs on non-Posix platforms requires tools that aren't part
 of the standard distribution of the OS.  The platform-specific README