build: Bump library version

From: Chuck Lever <cel@seurat.1015granger.net>

According to the libtool library version rules, because new APIs
have been added, the library version has to be updated.

And make it easier to remember to update the library version for
each release.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Steve Dickson <steved@redhat.com>

1 files changed, 27 insertions, 0 deletions

diff --git a/configure.ac b/configure.ac
index 99a0d33..06f2fca 100644
--- a/configure.ac
+++ b/configure.ac
@@ -5,6 +5,33 @@ AC_CONFIG_SRCDIR([src/auth_des.c])
 AC_CONFIG_MACRO_DIR([m4])
 AC_PROG_CC
 
+# LT_VERSION_INFO="current:revision:age"
+#
+# From the libtool manual:
+#
+# 1.  Start with version information of 0:0:0 for each libtool library.
+# 2.  Update the version information only immediately before a public
+#     release of your software. More frequent updates are unnecessary,
+#     and only guarantee that the current interface number gets larger faster.
+# 3.  If the library source code has changed at all since the last update,
+#     then increment revision (c:r:a becomes c:r+1:a).
+# 4.  If any interfaces have been added, removed, or changed since the last
+#     update, increment current, and set revision to 0.
+# 5.  If any interfaces have been added since the last public release,
+#     then increment age.
+# 6.  If any interfaces have been removed since the last public release,
+#     then set age to 0.
+#
+# _Never_ try to set the interface numbers so that they correspond to the
+# release number of your package. This is an abuse that only fosters
+# misunderstanding of the purpose of library versions.
+#
+# In addition to these rules, symbol versioning is now in effect. soname
+# changes should be avoided.
+#
+LT_VERSION_INFO="2:0:1"
+AC_SUBST([LT_VERSION_INFO])
+
 AC_CHECK_HEADER([gssapi/gssapi.h], [HAVE_GSSAPI_H=yes], [HAVE_GSSAPI_H=no])
 
 AC_ARG_ENABLE(gssapi,