Compiler error

[Yannick Francken]

> I have added a new .c file to the renderer part in the visual studio
> (.NET 2003) project file. In that file there is only one dummy
> function "void test(void) {}". When I try to call this function from
> tr_backend.c, this results in a linking error. If I put this dummy
> function in a random other .c file, there are no problems. <snip/>

It seems that the added .c file was recognized as a C++ file for some
reason, which causes the linking error.