Add Git version string support.

Introduce a script to auto-generate version strings. Use `git describe`
to create descriptive version strings when building from a Git checkout,
use ".version" files for release tarballs.

Signed-off-by: Lukas Fleischer <calcurse@cryptocrack.de>

.gitignore

@@ -11,6 +11,7 @@ depcomp
 install-sh
 missing
 stamp-h1
+.version
 autom4te.cache/
 m4/
 

Makefile.am

@@ -7,3 +7,7 @@ SUBDIRS = doc po src
 EXTRA_DIST = \
 	INSTALL \
 	ABOUT-NLS
+
+BUILT_SOURCES = $(top_srcdir)/.version
+$(top_srcdir)/.version:
+	echo $(VERSION) > $@-t && mv $@-t $@

build-aux/git-version-gen

@@ -0,0 +1,24 @@
+#!/bin/sh
+
+if [ "$#" -ne 1 ]
+then
+  echo "usage: git-version-gen <verfile>" >&2
+  exit 1
+fi
+
+VERFILE="$1"
+
+if [ -d '.git' ]
+then
+  VERSION=`git describe --abbrev=4 --match='v[0-9]*' --dirty | sed 's/^v//'`
+  echo -n "$VERSION" > "$VERFILE"
+fi
+
+if [ -f "$VERFILE" ]
+then
+  cat "$VERFILE"
+else
+  echo "git-version-gen: unknown version number." >&2
+  exit 1
+fi
+

configure.ac

@@ -2,7 +2,9 @@
 #                                                                           Init
 #-------------------------------------------------------------------------------
 AC_PREREQ(2.59)
-AC_INIT(calcurse, 2.8, bugs@calcurse.org)
+AC_INIT([calcurse],
+        m4_esyscmd([build-aux/git-version-gen .version]),
+        [bugs@calcurse.org])
 AM_INIT_AUTOMAKE
 #m4_ifdef([AM_SILENT_RULES],[AM_SILENT_RULES([yes])])
 AM_GNU_GETTEXT([external])