我试图在我的 MacBook Pro（OSX 10.9.5）上编译 UMLGraph，并在尝试运行“ant build.xml”时出错。有人遇到过这个问题吗？这是错误：
UMLGraph-5.7_2.3-SNAPSHOT$ ant build.xml
Buildfile: /Users/jeremy/UMLGraph-5.7_2.3-SNAPSHOT/build.xml
[echo] git describe --abbrev=6 => 'version'
BUILD FAILED
/Users/jeremy/UMLGraph-5.7_2.3-SNAPSHOT/build.xml:50: The following error occurred while executing this line:
/Users/jeremy/UMLGraph-5.7_2.3-SNAPSHOT/build.xml:27: exec returned: 128
Total time: 1 second
这是来自 build.xml 的第 50 行及其上方几行的片段：
23 <sequential>
24 <echo message="git describe --abbrev=6 => '@{outputproperty}'"/>
25 <exec executable="git"
26 failonerror="true"
27 outputproperty="@{outputproperty}">
28 <arg value="describe"/>
29 <arg value="--abbrev=6"/>
30 <arg value="HEAD"/>
31 <redirector>
32 <outputfilterchain>
33 <tokenfilter>
34 <replaceregex pattern="R" replace=""/>
35 <replaceregex pattern="_" replace="."/>
36 <replaceregex pattern="-" replace="."/>
37 <replaceregex pattern="(-.*)$" replace="-SNAPSHOT"/>
38 </tokenfilter>
39 </outputfilterchain>
40 </redirector>
41 </exec>
42 <echo message="gitversion returned '${@{outputproperty}}'"/>
43 </sequential>
44 </macrodef>
45
46 <!-- define Maven coordinates; see https://docs.sonatype.org/display/Repository/Sonatype+OSS+Maven+Repository+Usage+Guide#SonatypeOSSMavenRepositoryUsageGuide-7c.DeploySnaps hotsandStageReleaseswithAnt -->
47 <property name="groupId" value="org.umlgraph" />
48 <property name="artifactId" value="UmlGraph" />
49 <!-- <property name="version" value="1.0-SNAPSHOT" /> -->
50 <gitversion outputproperty="version"/>
以下是 README.txt 中的说明：
UMLGraph - Declarative Drawing of UML Diagrams
UMLGraph allows the declarative specification and drawing of
UML class and sequence diagrams. You can browse the system's
documentation from the doc/index.html page, or print it from
doc/indexw.html.
To install the elements required to run UMLGraph, simply copy
the contents of the lib directory to a location consistent with
your installation's conventions (for example to /usr/local/lib).
To compile the Java doclet from the source code run ant on the
build.xml file.
If you change the source code, you can run regression tests by
executing "ant test".
Project home page: http://www.umlgraph.org
GitHub page: git@github.com:dspinellis/UMLGraph.git
Diomidis Spinellis - November 2005, August 2008, April 2012
我按照说明将文件从 lib/ 复制到 /usr/local/lib，但似乎我没有正确构建它。
谢谢你的帮助。