Use git's version number for releases.

This will allow more specific version numbers, while simplifying a
proper release down to a tag and make dist.

During development, ./version.sh needs to run periodically to update
the version number.  I'd recommend just adding a call to version.sh as
a git post commit hook:

% cat .git/hooks/post-commit

echo "Updating version."
./version.sh

(and make sure the file is executable)

1 files changed, 8 insertions, 0 deletions

diff --git a/version.sh b/version.sh
new file mode 100755
index 0000000..8a58aef
--- /dev/null
+++ b/version.sh
@@ -0,0 +1,8 @@
+#!/bin/sh
+
+if git describe > version.tmp
+then
+    echo "m4_define([VERSION_NUMBER], [`tr -d '\n' < version.tmp`])" \
+        > version.m4
+fi
+rm version.tmp