[BUGFIX] Cleaner failure message if PCRE headers can't be found
[BUGFIX] Cleaner failure message if PCRE headers can't be found

Fixes #11

sfgeorge/ruby_speech,sfgeorge/ruby_speech,sfgeorge/ruby_speech,adhearsion/ruby_speech,adhearsion/ruby_speech,benlangfeld/ruby_speech,adhearsion/ruby_speech,benlangfeld/ruby_speech,benlangfeld/ruby_speech