build: add hint for a2x error message

Display:

  a2x not found, please install asciidoc, or pass --disable-man-doc

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/configure.ac b/configure.ac
index 816e920156ee94b61476acc72d487886c685d202..80a6481321781c00c5299487103b05ddde89718d 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -53,7 +53,7 @@ CHECK_GCC_FVISIBILITY
 AS_IF([test "x$enable_man_doc" = "xyes"], [
        AC_CHECK_PROG(A2X, [a2x], [a2x], [no])
        AS_IF([test "$A2X" = "no" -a ! -f "${srcdir}/doc/nft.8"],
-            [AC_MSG_ERROR([a2x not found, please install asciidoc])])
+            [AC_MSG_ERROR([a2x not found, please install asciidoc, or pass --disable-man-doc])])
 ])
 
 PKG_CHECK_MODULES([LIBMNL], [libmnl >= 1.0.4])