Don't shell out to git some more.

Update lib/jgit-describe.jar to a version that is a bit less strict about possible missing tags.

Change-Id: I8642e56da686879f56054fea14efa99ce5a6438e
Reviewed-on: http://gerrit.dmdirc.com/2302
Automatic-Compile: DMDirc Build Manager
Reviewed-by: Chris Smith <chris@dmdirc.com>

build-installer.xml

@@ -6,6 +6,12 @@
         <classpath location="lib/nsisant-1.3.jar" />
     </taskdef>
 
+    <taskdef name="git-describe" classname="org.mdonoughe.JGitDescribeTask">
+        <classpath>
+            <fileset dir="lib" includes="*jgit*.jar"/>
+        </classpath>
+    </taskdef>
+
     <target name="installer"
             description="Build the installer.">
         <exec executable="bash" dir="modules/installer" resultproperty="installer.result">
@@ -61,22 +67,7 @@
 
     <target name="installer-nsis" description="Builds the Windows installer"
         depends="jar">
-       <exec executable="git" outputproperty="nsis.lastcommit">
-          <arg value="--git-dir=modules/installer/.git"/>
-          <arg value="rev-list"/>
-          <arg value="--max-count=1"/>
-          <arg value="HEAD"/>
-          <arg value="--"/>
-          <arg value="windows"/>
-       </exec>
-
-       <exec executable="git" outputproperty="version.git.nsis">
-          <arg value="--git-dir=modules/installer/.git"/>
-          <arg value="describe"/>
-          <arg value="--tags"/>
-          <arg value="--always"/>
-          <arg value="${nsis.lastcommit}"/>
-       </exec>
+       <git-describe dir="modules/installer/.git" property="version.git.nsis" subdir="windows" />
 
         <mkdir dir="modules\installer\windows\files\" />
         <mkdir dir="modules\installer\output\" />

build-versioning.xml

@@ -34,10 +34,9 @@ version:
     <target name="-add-version" depends="-add-git-version"/>
 
     <target name="-add-git-version" if="is.git">
-        <exec executable="git" output="${version.config}" append="true">
-            <arg value="describe"/>
-            <arg value="--tags"/>
-        </exec>
+        <git-describe dir=".git" property="git.version" />
+        <echo file="${version.config}" append="true">${git.version}
+</echo>
     </target>
 
     <target name="-init-channel" unless="channel">