#232 Patches for TestIndexSearcher failures

[Stephan Bergmann]

(Not sure if there are better ways to offer patches for this project than to file a bug.)

make cl_test && make test failed for me with the default RelWithDebInfo (i.e., optimizing) configuration on Fedora 30 (i.e., with GCC 9.1). In "CLucene IndexSearcher Test" it would:

• either occasionally deadlock, addressed with the attached 0002-Avoid-deadlock-in-TestIndexSearcher.patch;
• or else consistenly fail with a SIGSEGV, addressed with the attached 0001-Make-sure-to-return-value-from-non-void-function.patch (see commit message there for details).