[build]: Detangle pdfroff, gropdf config (2/2).

* m4/groff.m4: Give pdfroff its own Autoconf macros to handle dependency
  checking, build objectives, and user notice.

  (GROFF_PDFROFF_DEPENDENCIES_CHECK): New macro requires
  `GROFF_AWK_PATH` and `GROFF_GHOSTSCRIPT_PATH`, determines whether
  pdfroff can be used at build time, and (if not) constructs part of
  message to be shown to user explaining why.

  (GROFF_PDFROFF_PROGRAM_NOTICE): New macro requires
  `GROFF_PDFROFF_DEPENDENCIES_CHECK` and emits message if needed.

  (GROFF_GHOSTSCRIPT_AVAILABILITY_NOTICE): Drop mention of impact on
  pdfroff since its dedicated notice covers this now.

* configure.ac: Call the new macros at appropriate times.  Produce a new
  Automake macro, `USE_PDFROFF`, to replace inapposite use of
  `USE_GROPDF` in pdfmark.am.

* contrib/pdfmark/pdfmark.am: Use `USE_PDFROFF` instead of `USE_GROPDF`.

1 files changed, 42 insertions, 2 deletions

diff --git a/m4/groff.m4 b/m4/groff.m4
index a99691e41..fcc676f64 100644
--- a/m4/groff.m4
+++ b/m4/groff.m4
@@ -259,6 +259,35 @@ AC_DEFUN([GROFF_AWK_NOTICE], [
   fi
 ])
 
+AC_DEFUN([GROFF_PDFROFF_DEPENDENCIES_CHECK], [
+  AC_REQUIRE([GROFF_AWK_PATH])
+  AC_REQUIRE([GROFF_GHOSTSCRIPT_PATH])
+
+  use_pdfroff=no
+  pdfroff_missing_deps=
+
+  test "$AWK" = missing && pdfroff_missing_deps="awk"
+
+  if test "$GHOSTSCRIPT" = missing
+  then
+    verb=is
+
+    if test -n "$pdfroff_missing_deps"
+    then
+      pdfroff_missing_deps="$pdfroff_missing_deps and "
+      verb=are
+    fi
+    pdfroff_missing_deps="${pdfroff_missing_deps}Ghostscript $verb"
+  fi
+
+  if test -z "$pdfroff_missing_deps"
+  then
+    use_pdfroff=yes
+  fi
+
+  AC_SUBST([use_pdfroff])
+])
+
 AC_DEFUN([GROFF_GROPDF_DEPENDENCIES_CHECK], [
   AC_REQUIRE([GROFF_GHOSTSCRIPT_PATH])
   AC_REQUIRE([GROFF_URW_FONTS_CHECK])
@@ -275,6 +304,19 @@ AC_DEFUN([GROFF_GROPDF_DEPENDENCIES_CHECK], [
   AC_SUBST([use_gropdf])
 ])
 
+AC_DEFUN([GROFF_PDFROFF_PROGRAM_NOTICE], [
+  AC_REQUIRE([GROFF_PDFROFF_DEPENDENCIES_CHECK])
+
+  if test "$use_pdfroff" = no
+  then
+    AC_MSG_NOTICE(['pdfroff' will not be functional.
+
+  Because $pdfroff_missing_deps missing, 'pdfroff' will not operate
+  and the 'pdfmark.pdf' document will not be available.
+])
+  fi
+])
+
 AC_DEFUN([GROFF_GROPDF_PROGRAM_NOTICE], [
   AC_REQUIRE([GROFF_GROPDF_DEPENDENCIES_CHECK])
 
@@ -487,8 +529,6 @@ AC_DEFUN([GROFF_GHOSTSCRIPT_AVAILABILITY_NOTICE], [
 
   'grohtml' will have reduced function, being unable to produce
   documents using the 'tbl' preprocessor.
-
-  Further, 'pdroff' will not work.
     ])
   fi
 ])