Makefile: Introduce Make_global.am

Analogous to libnftnl's build system, define libnftables interface
version in a variable in Make_global.am.

Suggested-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 21 insertions, 0 deletions

diff --git a/Make_global.am b/Make_global.am
new file mode 100644
index 00000000..713d9583
--- /dev/null
+++ b/Make_global.am
@@ -0,0 +1,21 @@
+# This is _NOT_ the library release version, it's an API version.
+# Extracted from Chapter 6 "Library interface versions" of the libtool docs.
+#
+# <snippet>
+# Here are a set of rules to help you update your library version information:
+#
+# 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.
+# </snippet>
+#
+libnftables_LIBVERSION=1:0:0