justinmk/vim-syntax-extra — pull request #5 by Zi0P4tch0 (2014-10-21 12:50:37+00:00)
Title: Added support for Xcode *.ym and *.lm Flex/Bison files

Xcode uses *.ym and *.lm extensions when it comes to mixing Flex/Bison with Objective-C code.