Rename mandoc_getarg() to roff_getarg() and pass it the roff parser

struct as an argument such that after copy-in, it can call roff_expand()
once again, which used to be called roff_res() before this.  This
fixes a subtle low-level roff(7) parsing bug reported by Fabio
Scotoni <fabio at esse dot ch> in the 4.4BSD-Lite2 mdoc.samples(7)
manual page, because that page used an escaped escape sequence in
a macro argument.

To expand escaped escape sequences in quoted mdoc(7) arguments, too,
stop bypassing the call to roff_getarg() in mdoc_argv.c, function args()
for this case.  This does not solve the case of escaped escape sequences
in quoted .Bl -column phrases yet.

Because roff_expand() can make the string longer, roff_getarg() can no
longer operate in-place but needs to malloc(3) the returned string.
In the high-level parsers, free(3) that string after processing it.

3 files changed, 14 insertions, 13 deletions

diff --git a/regress/man/RS/REarg.in b/regress/man/RS/REarg.in
index 27af5017..7901d3cf 100644
--- a/regress/man/RS/REarg.in
+++ b/regress/man/RS/REarg.in
@@ -1,8 +1,9 @@
-.\" $OpenBSD: REarg.in,v 1.3 2017/07/04 14:53:23 schwarze Exp $
-.TH RS-REARG 1 "January 24, 2015"
+.\" $OpenBSD: REarg.in,v 1.4 2018/12/21 16:58:49 schwarze Exp $
+.TH RS-REARG 1 "December 21, 2018"
 .SH NAME
 RS-REarg \- arguments to the RE macro
 .SH DESCRIPTION
+.nr one 1
 level 1
 .RS 4n 2i
 level 2
@@ -10,13 +11,13 @@ level 2
 level 3
 .RE 2a
 back to 2
-.RE 1b
+.RE \n[one]b
 back to 1
 .RS 4n
 level 2
 .RS 2n
 level 3
-.RE 1c
+.RE "\\n[one]c"
 back to 1
 .RS 4n
 level 2
@@ -24,4 +25,4 @@ level 2
 level 3
 .RE 0d
 back to 1
-.RE 1e
+.RE \\n[one]e
diff --git a/regress/man/RS/REarg.out_ascii b/regress/man/RS/REarg.out_ascii
index 747e037b..45326a88 100644
--- a/regress/man/RS/REarg.out_ascii
+++ b/regress/man/RS/REarg.out_ascii
@@ -20,4 +20,4 @@ DDEESSCCRRIIPPTTIIOONN
 
 
 
-OpenBSD                        January 24, 2015                    RS-REARG(1)
+OpenBSD                        December 21, 2018                   RS-REARG(1)
diff --git a/regress/man/RS/REarg.out_lint b/regress/man/RS/REarg.out_lint
index 457ccb15..a912a7e5 100644
--- a/regress/man/RS/REarg.out_lint
+++ b/regress/man/RS/REarg.out_lint
@@ -1,7 +1,7 @@
-mandoc: REarg.in:7:8: ERROR: skipping excess arguments: RS ... 2i
-mandoc: REarg.in:11:6: ERROR: skipping excess arguments: RE ... a
-mandoc: REarg.in:13:6: ERROR: skipping excess arguments: RE ... b
-mandoc: REarg.in:19:6: ERROR: skipping excess arguments: RE ... c
-mandoc: REarg.in:25:6: ERROR: skipping excess arguments: RE ... d
-mandoc: REarg.in:27:6: ERROR: skipping excess arguments: RE ... e
-mandoc: REarg.in:27:2: ERROR: fewer RS blocks open, skipping: RE 1
+mandoc: REarg.in:8:8: ERROR: skipping excess arguments: RS ... 2i
+mandoc: REarg.in:12:6: ERROR: skipping excess arguments: RE ... a
+mandoc: REarg.in:14:6: ERROR: skipping excess arguments: RE ... b
+mandoc: REarg.in:20:7: ERROR: skipping excess arguments: RE ... c
+mandoc: REarg.in:26:6: ERROR: skipping excess arguments: RE ... d
+mandoc: REarg.in:28:6: ERROR: skipping excess arguments: RE ... e
+mandoc: REarg.in:28:2: ERROR: fewer RS blocks open, skipping: RE 1