Mac OS X will be detected as a mac and not as Linux


git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@132 8db76d5a-ed1c-0410-87a9-c151d255dfc7

common.ant.xml

diff --git a/common.ant.xml b/common.ant.xml
index cad3665..19d2ef5 100755
--- a/common.ant.xml
+++ b/common.ant.xml
@@ -6,11 +6,19 @@
 	<fail unless="project.valid" message="This build file is in an inconsistent state." />
 
 	<condition property="build.host.platform" value="linux">
-		<os family="unix" />
+		<and>
+			<os family="unix" />
+			<not>
+				<contains string="${os.name}" substring="mac" casesensitive="false"/>
+			</not>
+		</and>
 	</condition>
 
 	<condition property="build.host.platform" value="mac">
-		<os family="mac" />
+                <and>
+			<os family="unix" />
+			<contains string="${os.name}" substring="mac" casesensitive="false" />
+		</and>
 	</condition>
 
 	<condition property="build.host.platform" value="windows">