build: don't require perl when building from a tarball

But do ensure -- in all other circumstances -- that the man/*.1
files are rebuilt whenever the version number changes.
* configure.ac (SRC_VERSION_C): Define.
* man/Makefile.am (dist_man1_MANS): Rename from $(man1_MANS),
so that we distribute those pesky man/*.1 files.
(EXTRA_DIST): Reflect name change.
(MAINTAINERCLEANFILES): Define this, not DISTCLEANFILES,
now that these generated files are distributed.
($(dist_man1_MANS)): Depend on $(SRC_VERSION_C), so we get the
full dependency when not building from a tarball.

1 files changed, 13 insertions, 0 deletions

diff --git a/configure.ac b/configure.ac
index 45e0fab..1afc344 100644
--- a/configure.ac
+++ b/configure.ac
@@ -144,6 +144,19 @@ fi
 AC_FUNC_CLOSEDIR_VOID
 AC_FUNC_FORK
 
+# When .tarball-version exists, we're building from a tarball
+# and must not make man/*.1 files depend on the generated src/version.c,
+# because that would induce a requirement to run the help2man perl script.
+# We are not yet prepared to make perl a build-from-tarball requirement.
+# Hence, here we detect .tarball-version existence.  When not present,
+# we define a variable to be used in man/Makefile.am to induce the
+# proper dependency (so that man/*.1 will be rebuilt upon any version change),
+# but not when built from a tarball.
+AC_SUBST([SRC_VERSION_C])
+test -f $srcdir/.tarball-version \
+  && SRC_VERSION_C= \
+  || SRC_VERSION_C=../src/version.c
+
 AM_GNU_GETTEXT([external], [need-ngettext])
 AM_GNU_GETTEXT_VERSION([0.17])
 XGETTEXT="AWK='$AWK' \$(SHELL) \$(top_srcdir)/exgettext $XGETTEXT"