Improve lopsub error diagnostics.

[tfortune.git] / configure.ac

diff --git a/configure.ac b/configure.ac
index 57e7d200f35c9bdb9bc64ed9e38a210c7a6b4618..0518719ab1018e147f9ddcbd88df5f3e80d92279 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -16,7 +16,6 @@ AC_DEFUN([REQUIRE_EXECUTABLE], [
 REQUIRE_EXECUTABLE([m4])
 REQUIRE_EXECUTABLE([flex])
 REQUIRE_EXECUTABLE([bison])
-REQUIRE_EXECUTABLE([lopsubgen])
 
 HAVE_LOPSUB=yes
 AC_CHECK_HEADER(lopsub.h, [], [HAVE_LOPSUB=no])
@@ -24,7 +23,9 @@ AC_CHECK_LIB([lopsub], [lls_merge], [], [HAVE_LOPSUB=no])
 if test $HAVE_LOPSUB == no; then AC_MSG_ERROR([
        The lopsub library is required to build this software, but
        the above checks indicate it is not installed on your system.
-       Run the following command to download a copy.
+
+       On Debian/Ubuntu systems you mny install the liblopsub-dev package.
+       Alternatively, run the following command to download a copy.
                git clone git://git.tuebingen.mpg.de/lopsub.git
        Install the library, then run this configure script again.
 
@@ -37,4 +38,5 @@ if test $HAVE_LOPSUB == no; then AC_MSG_ERROR([
                export LDFLAGS=-L\$pfx/lib
 ])
 fi
+REQUIRE_EXECUTABLE([lopsubgen])
 AC_OUTPUT