docs: drop asciidoc7compatible flag

When we made the switch to supporting asciidoc 8 in 4c7100a
(Documentation: adjust to AsciiDoc 8, 2007-06-14), we were
able to leave most of the documentation intact by defining
asciidoc7compatible.

Since commit 6cf378f (docs: stop using asciidoc no-inline-literal,
2012-04-26), we don't support versions of asciidoc older
than 8.4.1, which is when inline literals were introduced.
Therefore there is not much point in keeping our
documentation compatible with asciidoc 7.

So we are now free to drop the asciidoc7compatible flag and
update the documentation itself to assume asciidoc8.
Fortunately, doing the latter is very easy; we weren't using
any of the constructs impacted by asciidoc7compatible, so
there are no changes to make.

The reason is somewhat subtle. The asciidoc7compatible
affects only super/sub-scripts ("^" and "~") and index
terms. We don't use the latter at all. Nor we do we use the
former, but we did have to protect them from accidental
expansion in constructs like "rev^1". However, all of our
uses of "~" and "^" are either in code blocks (which are
rendered literally), or inside backticks. Prior to 6cf378f,
backticks were not inline literals, and needed proper
quoting. But post-6cf378f, we don't have to worry whether we
are using the old or new rules, as those characters are not
interpreted at all in either case.

I verified that the result of "make install-html
install-man" is identical before and after this patch on
asciidoc 8.6.7.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/Makefile

@@ -65,12 +65,6 @@ endif
 -include ../config.mak.autogen
 -include ../config.mak
 
-#
-# For asciidoc ...
-#	-7.1.2,	set ASCIIDOC7
-#	8.0-,	no extra settings are needed
-#
-
 #
 # For docbook-xsl ...
 #	-1.68.1,	no extra settings are needed?
@@ -81,9 +75,6 @@ endif
 #	1.73.0-,	no extra settings are needed
 #
 
-ifndef ASCIIDOC7
-ASCIIDOC_EXTRA += -a asciidoc7compatible
-endif
 ifdef DOCBOOK_XSL_172
 ASCIIDOC_EXTRA += -a git-asciidoc-no-roff
 MANPAGE_XSL = manpage-1.72.xsl

Makefile

@@ -203,8 +203,6 @@ all::
 # Define NO_ST_BLOCKS_IN_STRUCT_STAT if your platform does not have st_blocks
 # field that counts the on-disk footprint in 512-byte blocks.
 #
-# Define ASCIIDOC7 if you want to format documentation with AsciiDoc 7
-#
 # Define DOCBOOK_XSL_172 if you want to format man pages with DocBook XSL v1.72
 # (not v1.73 or v1.71).
 #
@@ -1834,10 +1832,6 @@ ifndef V
 endif
 endif
 
-ifdef ASCIIDOC7
-	export ASCIIDOC7
-endif
-
 ifdef NO_INSTALL_HARDLINKS
 	export NO_INSTALL_HARDLINKS
 endif

config.mak.in

@@ -28,7 +28,6 @@ VPATH = @srcdir@
 export exec_prefix mandir
 export srcdir VPATH
 
-ASCIIDOC7=@ASCIIDOC7@
 NEEDS_SSL_WITH_CRYPTO=@NEEDS_SSL_WITH_CRYPTO@
 NO_OPENSSL=@NO_OPENSSL@
 NO_CURL=@NO_CURL@

configure.ac

@@ -437,21 +437,14 @@ if test -n "$ASCIIDOC"; then
 	AC_MSG_CHECKING([for asciidoc version])
 	asciidoc_version=`$ASCIIDOC --version 2>/dev/null`
 	case "${asciidoc_version}" in
-	asciidoc' '7*)
-		ASCIIDOC7=YesPlease
-		AC_MSG_RESULT([${asciidoc_version} > 7])
-		;;
 	asciidoc' '8*)
-		ASCIIDOC7=
 		AC_MSG_RESULT([${asciidoc_version}])
 		;;
 	*)
-		ASCIIDOC7=
 		AC_MSG_RESULT([${asciidoc_version} (unknown)])
 		;;
 	esac
 fi
-AC_SUBST(ASCIIDOC7)
 
 
 ## Checks for libraries.