add checks for docbook2man
diff --git a/configure.in b/configure.in
index 50a71ff..09b5c71 100644
--- a/configure.in
+++ b/configure.in
@@ -311,6 +311,12 @@
AC_DEFINE(FLAC__HAS_DOXYGEN)
fi
+AC_CHECK_PROGS(DOCBOOK_TO_MAN, docbook-to-man docbook2man)
+AM_CONDITIONAL(FLaC__HAS_DOCBOOK_TO_MAN, test -n "$DOCBOOK_TO_MAN")
+if test -n "$DOCBOOK_TO_MAN" ; then
+AC_DEFINE(FLAC__HAS_DOCBOOK_TO_MAN)
+fi
+
AC_CHECK_PROGS(NASM, nasm)
AM_CONDITIONAL(FLaC__HAS_NASM, test -n "$NASM")
if test -n "$NASM" ; then
@@ -337,6 +343,7 @@
AH_TEMPLATE(FLAC__EXHAUSTIVE_TESTS, [define to run even more tests])
AH_TEMPLATE(FLAC__VALGRIND_TESTING, [define to enable use of Valgrind in testers])
AH_TEMPLATE(FLAC__HAS_DOXYGEN, [define if you have Doxygen])
+AH_TEMPLATE(FLAC__HAS_DOCBOOK_TO_MAN, [define if you have docbook-to-man or docbook2man])
AH_TEMPLATE(FLAC__HAS_ID3LIB, [define if you have the id3lib library])
AH_TEMPLATE(FLAC__HAS_NASM, [define if you have the NASM assembler])
AH_TEMPLATE(FLAC__HAS_OGG, [define if you have the ogg library])