configure: Suggest to install liblopsub-dev.

diff --git a/configure.ac b/configure.ac
index 9e90ae5d6745d335f93b9eb3f7c8f8e44630964e..efb96a3b45a6a91442f502ec24532edbafcd13fc 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -80,7 +80,8 @@ 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 may install the liblopsub-dev package.
+       Alternatively, run the following command to download a copy.
                git clone https://git.tuebingen.mpg.de/lopsub.git
        Install the library, then run this configure script again.
 ])