Problem still exists with variables which are declared "extern", defined in one file, and accessed in another. Seems to depend on data type modifier:
Variables of type unsigned char, signed char, unsigned short etc. do not work (error says "variable already exists"), whereas variables of type char, int, or short seem to work ok. At least there is no error message. I did not do a functional test in this case.
Steps to reproduce:
Build a project containing 3 files: Main.c, module1.h, and module1.c.