[man pages]: Don't doc compat wrappers if unused.

[man pages]: Don't document macro package compatibility wrapper
directory if it's not used.

* Makefile.am (.man): Use sed to replace '@COMPATIBILITY_WRAPPERS@' in
  man page text with value of `compatibility_wrappers` shell variable.
  Document its purpose.
* src/preproc/eqn/eqn.1.man (Description):
* src/preproc/grn/grn.1.man (Options):
* src/roff/groff/groff.1.man (Installation directories):
* src/roff/troff/troff.1.man (Environment): Mention `@SYSTEMMACRODIR`
  only if `@COMPATIBILITY_WRAPPERS` expands to something other than "no"
  (it could be "yes" or "manual").

Thanks to Alexander Kanavin and Jeremy Puhlman for the report.

ChangeLog

@@ -1,3 +1,20 @@
+2022-10-24  G. Branden Robinson <g.branden.robinson@gmail.com>
+
+	[man pages]: Don't document macro package compatibility wrapper
+	directory if it's not used.
+
+	* Makefile.am (.man): Use sed to replace
+	'@COMPATIBILITY_WRAPPERS@' in man page text with value of
+	`compatibility_wrappers` shell variable.  Document its purpose.
+	* src/preproc/eqn/eqn.1.man (Description):
+	* src/preproc/grn/grn.1.man (Options):
+	* src/roff/groff/groff.1.man (Installation directories):
+	* src/roff/troff/troff.1.man (Environment): Mention
+	`@SYSTEMMACRODIR` only if `@COMPATIBILITY_WRAPPERS` expands to
+	something other than "no" (it could be "yes" or "manual").
+
+	Thanks to Alexander Kanavin and Jeremy Puhlman for the report.
+
 2022-10-21  Robert Yang <liezhi.yang@windriver.com>
 
 	* font/devpdf/util/BuildFoundries.pl:

Makefile.am

@@ -849,6 +849,10 @@ MOSTLYCLEANFILES += $(prefixexecbin_SCRIPTS) $(bin_SCRIPTS) \
 # * For this target, no assurances about the good behavior of unusual
 #   characters in Makefile variables in other aspects of the groff build
 #   are offered.
+#
+# COMPATIBILITY_WRAPPERS is intended only for use in conditional
+# expressions in man pages (to see if the legacy macro package wrappers
+# feature is enabled) and not for expansion as formatted text.
 makevarescape=$(top_srcdir)/makevarescape.sed
 
 SUFFIXES += .man
@@ -858,6 +862,7 @@ SUFFIXES += .man
 	 sed -e "s|[@]APPDEFDIR[@]|`echo $(appdefdir) | sed -f $(makevarescape)`|g" \
 	     -e "s|[@]BINDIR[@]|`echo $(bindir) | sed -f $(makevarescape)`|g" \
 	     -e "s|[@]COMMON_WORDS_FILE[@]|`echo $(common_words_file) | sed -f $(makevarescape)`|g" \
+	     -e "s|[@]COMPATIBILITY_WRAPPERS[@]|$(compatibility_wrappers)|g" \
 	     -e "s|[@]DATASUBDIR[@]|`echo $(datasubdir) | sed -f $(makevarescape)`|g" \
 	     -e "s|[@]DEFAULT_INDEX[@]|`echo $(indexdir)/$(indexname) | sed -f $(makevarescape)`|g" \
 	     -e "s|[@]DEFAULT_INDEX_NAME[@]|`echo $(indexname) | sed -f $(makevarescape)`|g" \

src/preproc/eqn/eqn.1.man

@@ -148,7 +148,7 @@ in the directories given with the
 .B \-M
 option first,
 then in
-.IR @SYSTEMMACRODIR@ ,
+.if !'@COMPATIBILITY_WRAPPERS@'no' .IR @SYSTEMMACRODIR@ ,
 .IR @LOCALMACRODIR@ ,
 and finally in the standard macro directory
 .IR @MACRODIR@ .

src/preproc/grn/grn.1.man

@@ -881,7 +881,7 @@ files.
 .
 The default search path is the current directory,
 the home directory,
-.IR @SYSTEMMACRODIR@ ,
+.if !'@COMPATIBILITY_WRAPPERS@'no' .IR @SYSTEMMACRODIR@ ,
 .IR @LOCALMACRODIR@ ,
 and
 .IR @MACRODIR@ ,

src/roff/groff/groff.1.man

@@ -2034,11 +2034,13 @@ see
 PDF documentation directory.
 .
 .
+.if !'@COMPATIBILITY_WRAPPERS@'no' \{\
 .TP
 .I @SYSTEMMACRODIR@
 System macro package
 .RI ( tmac
 file) directory.
+.\}
 .
 .
 .\" ====================================================================

src/roff/troff/troff.1.man

@@ -801,8 +801,10 @@ options before these,
 then the current directory
 (only if in unsafe mode),
 the user's home directory,
+.if !'@COMPATIBILITY_WRAPPERS@'no' \{\
 a platform-specific directory
 .RI ( @SYSTEMMACRODIR@ ),
+.\}
 a site-specific directory
 .RI ( @LOCALMACRODIR@ ),
 and a standard location