BigApp: no viable alternative at character '\' when building the project

Description of problem:

After cloning the repository, if tried to build the project the error message is logged:

18:23:42,321 ERROR [stderr] (pool-16-thread-1) line 1:41 no viable alternative at character '\'
18:23:42,322 ERROR [stderr] (pool-16-thread-1) line 1:104 no viable alternative at character '\'
18:23:42,322 ERROR [stderr] (pool-16-thread-1) line 1:155 no viable alternative at character '\'

Version-Release number of selected component (if applicable):
6.0.0 CR2

How reproducible:
always

Steps to Reproduce:
1. clone the bigapp repo
2. build the package

Actual results:
"no viable alternative at character '\'" - as error message

Expected results:
no error messages at server log

Additional info:
This issue is related to Bug 983347. As workaround the Process should be opened in web Designer and saved again and then the build will work.