Content originally posted in LPCWare by CodeRedSupport on Sat Feb 19 09:12:58 MST 2011
It means they are excluded from the build. Anything with a 'hollowed out' letter (c/h) signifies it is excluded (i.e. will not be compiled).
As they are header files, that doesn't really matter, but you must have excluded them somehow - either the files individually, or the parent directory.