I am using Eclipse Juno with MFP 7.1 in a Mac.
I put my server address in Configure Build and Deploy Target http://example.com:80 and then use Run As > Run on MobileFirst Development Server.
In Windows, this updates my worklight.plist and wlclient.properties files with the new values for the server URL and port number, however in Mac the values remains MyMacBookPro.local as the server URL and the port number as 10080.
This is working for me using Eclipse Mars.2 and IBM MobileFirst Platform Studio 7.1.0.00-20160419-1518, on Mac.
Selected Run As > Run on MobileFirst Development Server
This shows "mbp-idan.local"
Selected Run As > Build Settings and Deploy Target, and changed the values as follows:
Selected Run As > Run on MobileFirst Development Server
Opened test\iphone\native\worklight.plist and I see the following:
<dict> <key>protocol</key> <string>http</string> <key>host</key> <string>example.com</string> <key>port</key> <string>80</string> <key>wlServerContext</key> <string>/helloworld/</string>