[man pages]: Define page-local `MR` fallback.

[man pages]: Provide page-local fallback definition of new `MR` macro.
I didn't think I was going to have to do this, but the premier site on
the web for viewing Linux man pages, Michael Kerrisk's man7.org, has
been pulling snapshots of the pages themselves without upgrading the
underlying macros, and so man page cross references set with `MR` are
getting lost in its presentations.  (I acknowledge: Ingo Schwarze warned
me something like this could happen.)  This definition is intended as a
stopgap measure only.  I want to revert this after groff 1.23 is
released and has spread to some reasonable degree.

* contrib/chem/chem.1.man:
* contrib/eqn2graph/eqn2graph.1.man:
* contrib/gdiffmk/gdiffmk.1.man:
* contrib/glilypond/glilypond.1.man:
* contrib/gperl/gperl.1.man:
* contrib/gpinyin/gpinyin.1.man:
* contrib/grap2graph/grap2graph.1.man:
* contrib/hdtbl/groff_hdtbl.7.man:
* contrib/mm/groff_mm.7.man:
* contrib/mm/groff_mmse.7.man:
* contrib/mm/mmroff.1.man:
* contrib/mom/groff_mom.7.man:
* contrib/pdfmark/pdfroff.1.man:
* contrib/pic2graph/pic2graph.1.man:
* contrib/rfc1345/groff_rfc1345.7.man:
* man/groff.7.man:
* man/groff_char.7.man:
* man/groff_diff.7.man:
* man/groff_font.5.man:
* man/groff_out.5.man:
* man/groff_tmac.5.man:
* man/roff.7.man:
* src/devices/grodvi/grodvi.1.man:
* src/devices/grohtml/grohtml.1.man:
* src/devices/grolbp/grolbp.1.man:
* src/devices/grolj4/grolj4.1.man:
* src/devices/gropdf/gropdf.1.man:
* src/devices/gropdf/pdfmom.1.man:
* src/devices/grops/grops.1.man:
* src/devices/grotty/grotty.1.man:
* src/devices/xditview/gxditview.1.man:
* src/preproc/eqn/eqn.1.man:
* src/preproc/eqn/neqn.1.man:
* src/preproc/grn/grn.1.man:
* src/preproc/pic/pic.1.man:
* src/preproc/preconv/preconv.1.man:
* src/preproc/refer/refer.1.man:
* src/preproc/soelim/soelim.1.man:
* src/preproc/tbl/tbl.1.man:
* src/roff/groff/groff.1.man:
* src/roff/nroff/nroff.1.man:
* src/roff/troff/troff.1.man:
* src/utils/addftinfo/addftinfo.1.man:
* src/utils/afmtodit/afmtodit.1.man:
* src/utils/grog/grog.1.man:
* src/utils/hpftodit/hpftodit.1.man:
* src/utils/indxbib/indxbib.1.man:
* src/utils/lkbib/lkbib.1.man:
* src/utils/lookbib/lookbib.1.man:
* src/utils/pfbtops/pfbtops.1.man:
* src/utils/tfmtodit/tfmtodit.1.man:
* src/utils/xtotroff/xtotroff.1.man:
* tmac/groff_man.7.man.in:
* tmac/groff_me.7.man:
* tmac/groff_ms.7.man:
* tmac/groff_trace.7.man:
* tmac/groff_www.7.man: Do it.

The sed script I used follows.  I patched neqn(1), which does not
require compatibility mode, by hand.

/^\.cp 0/a\
.\
.\\" Define fallback for groff 1.23's MR macro if the system lacks it.\
.de @@\
.  de MR\
.    ie \\n(.$=1 \\\
.      I \%\\$1\
.    el \\\
.      IR \%\\$1 (\\$2)\\$3\
.  \\\\.\
..\
.if  \\n(.g .if !d MR .@@\
.if !\\n(.g .@@\
.rm @@

7 files changed, 91 insertions, 0 deletions

diff --git a/man/groff.7.man b/man/groff.7.man
index 9a14bee2a..ab64f841e 100644
--- a/man/groff.7.man
+++ b/man/groff.7.man
@@ -28,6 +28,19 @@ language reference
 .do nr *groff_groff_7_man_C \n[.cp]
 .cp 0
 .
+.\" Define fallback for groff 1.23's MR macro if the system lacks it.
+.de @@
+.  de MR
+.    ie \n(.$=1 \
+.      I %\$1
+.    el \
+.      IR %\$1 (\$2)\$3
+.  \\.
+..
+.if  \n(.g .if !d MR .@@
+.if !\n(.g .@@
+.rm @@
+.
 .
 .\" ====================================================================
 .\" Setup
diff --git a/man/groff_char.7.man b/man/groff_char.7.man
index 188fb80d3..a004b8488 100644
--- a/man/groff_char.7.man
+++ b/man/groff_char.7.man
@@ -30,6 +30,19 @@ special character and glyph repertoire
 .do nr *groff_groff_char_7_man_C \n[.cp]
 .cp 0
 .
+.\" Define fallback for groff 1.23's MR macro if the system lacks it.
+.de @@
+.  de MR
+.    ie \n(.$=1 \
+.      I %\$1
+.    el \
+.      IR %\$1 (\$2)\$3
+.  \\.
+..
+.if  \n(.g .if !d MR .@@
+.if !\n(.g .@@
+.rm @@
+.
 .
 .\" ====================================================================
 .SH Description
diff --git a/man/groff_diff.7.man b/man/groff_diff.7.man
index b520e7129..afece2e70 100644
--- a/man/groff_diff.7.man
+++ b/man/groff_diff.7.man
@@ -29,6 +29,19 @@ and AT&T
 .do nr *groff_groff_diff_7_man_C \n[.cp]
 .cp 0
 .
+.\" Define fallback for groff 1.23's MR macro if the system lacks it.
+.de @@
+.  de MR
+.    ie \n(.$=1 \
+.      I %\$1
+.    el \
+.      IR %\$1 (\$2)\$3
+.  \\.
+..
+.if  \n(.g .if !d MR .@@
+.if !\n(.g .@@
+.rm @@
+.
 .
 .\" ====================================================================
 .\" Local definitions
diff --git a/man/groff_font.5.man b/man/groff_font.5.man
index a26003ed9..cace1aa32 100644
--- a/man/groff_font.5.man
+++ b/man/groff_font.5.man
@@ -28,6 +28,19 @@ device and font description files
 .do nr *groff_groff_font_5_man_C \n[.cp]
 .cp 0
 .
+.\" Define fallback for groff 1.23's MR macro if the system lacks it.
+.de @@
+.  de MR
+.    ie \n(.$=1 \
+.      I %\$1
+.    el \
+.      IR %\$1 (\$2)\$3
+.  \\.
+..
+.if  \n(.g .if !d MR .@@
+.if !\n(.g .@@
+.rm @@
+.
 .
 .\" ====================================================================
 .SH Description
diff --git a/man/groff_out.5.man b/man/groff_out.5.man
index 65386de45..f31fd3212 100644
--- a/man/groff_out.5.man
+++ b/man/groff_out.5.man
@@ -28,6 +28,19 @@ intermediate output format
 .do nr *groff_groff_out_5_man_C \n[.cp]
 .cp 0
 .
+.\" Define fallback for groff 1.23's MR macro if the system lacks it.
+.de @@
+.  de MR
+.    ie \n(.$=1 \
+.      I %\$1
+.    el \
+.      IR %\$1 (\$2)\$3
+.  \\.
+..
+.if  \n(.g .if !d MR .@@
+.if !\n(.g .@@
+.rm @@
+.
 .
 .\" ====================================================================
 .\" Setup
diff --git a/man/groff_tmac.5.man b/man/groff_tmac.5.man
index 20d1953d0..02dda7888 100644
--- a/man/groff_tmac.5.man
+++ b/man/groff_tmac.5.man
@@ -27,6 +27,19 @@ typesetting system
 .do nr *groff_groff_tmac_5_man_C \n[.cp]
 .cp 0
 .
+.\" Define fallback for groff 1.23's MR macro if the system lacks it.
+.de @@
+.  de MR
+.    ie \n(.$=1 \
+.      I %\$1
+.    el \
+.      IR %\$1 (\$2)\$3
+.  \\.
+..
+.if  \n(.g .if !d MR .@@
+.if !\n(.g .@@
+.rm @@
+.
 .
 .\" TODO: Consider parallelizing with our Texinfo node "Macro Packages".
 .\" ====================================================================
diff --git a/man/roff.7.man b/man/roff.7.man
index 9cdff7447..ad1386dad 100644
--- a/man/roff.7.man
+++ b/man/roff.7.man
@@ -31,6 +31,19 @@ typesetting
 .do nr *groff_roff_7_man_C \n[.cp]
 .cp 0
 .
+.\" Define fallback for groff 1.23's MR macro if the system lacks it.
+.de @@
+.  de MR
+.    ie \n(.$=1 \
+.      I %\$1
+.    el \
+.      IR %\$1 (\$2)\$3
+.  \\.
+..
+.if  \n(.g .if !d MR .@@
+.if !\n(.g .@@
+.rm @@
+.
 .
 .\" ====================================================================
 .SH Description