Fix OSX cmake build

Commit r260721(http://reviews.llvm.org/D17182) introduced the following error when building for OSX using cmake:

Undefined symbols for architecture x86_64:

"_PyInit__lldb", referenced from:
   -exported_symbol[s_list] command line option

ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

Adding '*' to the regex solves this problem, since it makes the symbol optional.

Reviewers: sivachandra, zturner, labath
Subscribers: lldb-commits
Differential Revision: http://reviews.llvm.org/D17384

llvm-svn: 261227