Compiler: move c2_assert to c2

[chqrlie]

• compute the assert string and function call at parse time
• add libc2 module in libs/libc/c2internals.c2i
• add auto_func function parameter attribute
• reject invalid combinations of auto_xxx attributes

[bvdberg]

It also has auto-arg changes.. please keep commits small so it's easier for me to review..

[chqrlie]

I just split this PR into 2 separate commits:

• one for the new auto_func attribute and other attribute fixes
• one for the c2_assert function migration to the library.

[bvdberg]

In which case will a.getCall() be nil?

[chqrlie]

the call expression is only constructed by the parser if asserts are enabled. The expression is always parsed and stored for the analyser.

[bvdberg]

I lookat the the PR again. It slows down parsing 16.1 -> 16.6 ms on avg on my system. Is there a reason we add the call during parsing? Otherwise it could follow the other AST changes and just store the basic info during parsing and only change the AST if asserts are enabled and the compiler is not in check-only mode. Then --check would be faster

[chqrlie]

Thanks for reviewing this again. Indeed I can delay constructing the call to the analyser and only if needed. I suspect the slowdown is due in large part to the conversion from SrcLoc to the location components, which was impacting the C source generation time only. Moving the construction to the analyser will impact the analysis time unless --check is selected. Improving the conversion method would accelerate the combined parsing + analysis + generation time.