moving math to core

[boggle]

should do for now, more to come later: all C99 calls, little details, (complex numbers when sensible),
more test code.

[boggle]

Please squash into one commit

[marijnh]

Doesn't pass:

failures:
    [run-pass] ./src/test/run-pass/triv-cast-be.rs
    [run-pass] ./src/test/run-pass/triv-cast-const.rs

$ rustc src/test/run-pass/triv-cast-be.rs

src/test/run-pass/triv-cast-be.rs:5:26: 5:26 error: unresolved typename: m_float
src/test/run-pass/triv-cast-be.rs:5 fn foo_float() -> m_float { ret 0.0 as m_float; }
                                                              ^
src/test/run-pass/triv-cast-be.rs:8:22: 8:22 error: unresolved typename: m_int
src/test/run-pass/triv-cast-be.rs:8 fn foo_int() -> m_int { ret 0 as m_int; }
                                                          ^
src/test/run-pass/triv-cast-be.rs:11:24: 11:24 error: unresolved typename: m_uint
src/test/run-pass/triv-cast-be.rs:11 fn foo_uint() -> m_uint { ret 0u as m_uint; }

[boggle]

Ah, forgot about those two, only ran check-*-std. Name-clash resolution mistake between ctypes/mtypes.

Concerning tail calls: Thanks for saying, I thought they are just unimplemented right now. I am strongly against not having them, the whole actor model kind-of rests on tail calls, could also be a nice basis for task migration in the future (be tailcall() at site xyz, no need to maintain "result back channel"), not to mention sane uses of functional programming.

In math I used them as an idiom for "really this function should just be reexported with another type", don't know how to do that differently (except perhaps by introducing export .. as ..)

[graydon]

Integrated, thanks.