Fix compile and test failures when troff is not groff

Fixes https://gitlab.com/man-db/man-db/-/issues/12.

* src/man.c (ONLY_TROFF_IS_GROFF): Only define if `HAS_TROFF` is
defined.
(init_html_pager): Only define if `TROFF_IS_GROFF` is defined.
(format_display): Mark `man_file` as unused if `TROFF_IS_GROFF` is not
defined.

* configure.ac: Substitute `troff_is_groff`.
* src/tests/Makefile.am (TESTS_ENVIRONMENT): Export `troff_is_groff`.
* src/tests/man-language-specific-requests: Adjust expected
language-specific requests if `troff_is_groff` is not `yes`.

* NEWS.md: Document this.

5 files changed, 33 insertions, 8 deletions

diff --git a/NEWS.md b/NEWS.md
index 3b62bfaa..6aa4ff42 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,3 +1,10 @@
+man-db 2.11.2
+=============
+
+Fixes:
+
+ * Fix compile and test failures when `troff` is not `groff`.
+
 man-db 2.11.1 (15 November 2022)
 ================================
 
diff --git a/configure.ac b/configure.ac
index cacf2391..fa1757c7 100644
--- a/configure.ac
+++ b/configure.ac
@@ -196,6 +196,7 @@ else
 	AC_CHECK_PROGS([troff], [troff gtroff])
 	TROFF=troff
 fi
+AC_SUBST([troff_is_groff])
 AC_SUBST([TROFF])
 if test -n "$troff"
 then
diff --git a/src/man.c b/src/man.c
index a55aa03a..713f41ef 100644
--- a/src/man.c
+++ b/src/man.c
@@ -263,11 +263,13 @@ static const char args_doc[] = N_("[SECTION] PAGE...");
 #  define ONLY_NROFF_WARNINGS OPTION_HIDDEN
 # endif
 
-# ifdef TROFF_IS_GROFF
-#  define ONLY_TROFF_IS_GROFF 0
-# else
-#  define ONLY_TROFF_IS_GROFF OPTION_HIDDEN
-# endif
+# ifdef HAS_TROFF
+#  ifdef TROFF_IS_GROFF
+#   define ONLY_TROFF_IS_GROFF 0
+#  else
+#   define ONLY_TROFF_IS_GROFF OPTION_HIDDEN
+#  endif
+# endif /* HAS_TROFF */
 
 /* Please keep these options in the same order as in parse_opt below. */
 static struct argp_option options[] = {
@@ -363,12 +365,14 @@ static struct argp_option options[] = {
 	{ 0 }
 };
 
+#ifdef TROFF_IS_GROFF
 static void init_html_pager (void)
 {
 	html_pager = getenv ("BROWSER");
 	if (!html_pager)
 		html_pager = PROG_BROWSER;
 }
+#endif /* TROFF_IS_GROFF */
 
 static error_t parse_opt (int key, char *arg, struct argp_state *state)
 {
@@ -1946,13 +1950,19 @@ static int format_display_and_save (decompress *d,
 }
 #endif /* MAN_CATS */
 
+#ifdef TROFF_IS_GROFF
+# define MAN_FILE_UNUSED
+#else /* !TROFF_IS_GROFF */
+# define MAN_FILE_UNUSED MAYBE_UNUSED
+#endif /* TROFF_IS_GROFF */
+
 /* Format a manual page with format_cmd and display it with disp_cmd.
  * Handle temporary file creation if necessary.
  * TODO: merge with format_display_and_save
  */
 static void format_display (decompress *d,
 			    pipeline *format_cmd, pipeline *disp_cmd,
-			    const char *man_file)
+			    const char *man_file MAN_FILE_UNUSED)
 {
 	pipeline *decomp = decompress_get_pipeline (d);
 	int format_status = 0, disp_status = 0;
diff --git a/src/tests/Makefile.am b/src/tests/Makefile.am
index 6491417b..3cadd2c9 100644
--- a/src/tests/Makefile.am
+++ b/src/tests/Makefile.am
@@ -22,7 +22,8 @@ TESTS_ENVIRONMENT = PATH=$(abs_builddir)/..:$$PATH; export PATH; \
 		    DBTYPE=$(DBTYPE); export DBTYPE; \
 		    MANDIR_LAYOUT=$(MANDIR_LAYOUT); export MANDIR_LAYOUT; \
 		    abs_top_builddir=$(abs_top_builddir); export abs_top_builddir; \
-		    OVERRIDE_DIR="$(override_dir)"; export OVERRIDE_DIR;
+		    OVERRIDE_DIR="$(override_dir)"; export OVERRIDE_DIR; \
+		    troff_is_groff=$(troff_is_groff); export troff_is_groff;
 # Each test must use the configure-detected shell, not necessarily /bin/sh.
 AM_LOG_FLAGS = $(SHELL)
 ALL_TESTS = \
diff --git a/src/tests/man-language-specific-requests b/src/tests/man-language-specific-requests
index 3c7a4137..5051d50b 100755
--- a/src/tests/man-language-specific-requests
+++ b/src/tests/man-language-specific-requests
@@ -35,9 +35,15 @@ write_page test 1 "$tmpdir/usr/share/man/xyzzy/man1/test.1" \
 write_page xyz 1 "$tmpdir/usr/share/man/man1/xyz.1" \
 	UTF-8 '' '' 'test \- top-level xyz page'
 
-cat >"$tmpdir/1.exp" <<'EOF'
+: >"$tmpdir/1.exp"
+# shellcheck disable=SC2154
+if [ "$troff_is_groff" = yes ]; then
+	cat >>"$tmpdir/1.exp" <<'EOF'
 .    mso xyzzy.tmac
 .hla xyzzy
+EOF
+fi
+cat >>"$tmpdir/1.exp" <<'EOF'
 test \- xyzzy language page for test
 EOF