Codechange: [OSX] Use more exact enum names where introduced with the 10.12 SDK.

The enum values still have the exact same numerical values, but the 10.12
SDK introduced more explicit names (e.g. like NSEventTypeApplicationDefined
instead of NSApplicationDefined) for several enum constants.
Use them when available.

(svn r17702) -Change: [OSX] Assure that the minimal OSX version is defined in all cases.
-Codechange: [OSX] Improve conditional defines for OS version dependant code.

(svn r7759) -Merge: makefile rewrite. This merge features:
- A proper ./configure, so everything needs to be configured only once, not for every make.
- Usage of makedepend when available. This greatly reduces the time needed for generating the dependencies.
- A generator for all project files. There is a single file with sources, which is used to generate Makefiles and the project files for MSVC.
- Proper support for OSX universal binaries.
- Object files for non-MSVC compiles are also placed in separate directories, making is faster to switch between debug and release compiles and it does not touch the directory with the source files.
- Functionality to make a bundle of all needed files for for example a nightly or distribution of a binary with all needed GRFs and language files.

Note: as this merge moves almost all files, it is recommended to make a backup of your working copy before updating your working copy.