Added a new variable TARGETSYSTEM, which is set to WINDOWS or LINUX according to
the desired system.

Calling make without parameters automatically sets the target to Linux.

Added a section for global settings for Windows and Linux.
Linux only needs -ncurses.
Windows needs additional stuff.

Relaxed the cross-compile target. The cross-compiler prefix now only needs to
contain mingw32, as there are many different versions out there.
Full height bionics window
Fix compilation on windows
Merge PR #920 - easier cross-compilation
Merge PR #1002 - Windows compilation fix
Merge PR #1001 - resizable bionics window