Attempt to get Mac OS configuration right
Deal with -Werror,-Wunused-private-field
Further adjustments for Mac OS

e.g. use target configs rather than separate projects
Fix Mac OS Yosemite problem

initially only for C7.
Chapter 7 / 18 - fix unused parameters.
Chapter 7 / 18 - use CHECK_THROWS() macro.
Ignore *.app.
Separate post build steps for Mac / PC