Moved (l/i48/ll)abs/div into LIBC

[ZERICO2005]

Moved the following functions from src/crt to src/libc since these functions use the C calling convention:

labs.src
ldiv.src
i48abs.src
i48div.src
llabs.src
lldiv.src

abs.src and div.src were already inside of src/libc.

I also cleaned up the code of and added timings to ineg, inot, ineg_fast, and inot_fast.

[ZERICO2005]

I undid the libcall absolute value functions commit to keep this PR simple. They can be added later in a different PR

[mateoconlechuga]

what no these are not libc functions.

[ZERICO2005]

They are the only functions in src/crt that follow the C calling convention to my knowledge. These functions are defined in <stdlib.h>.
ldivs.src and lrems.src use the LIBCALL convention, but ldiv.src does not

[mateoconlechuga]

Fine, why is there still a bunch of #if 1 in there

[ZERICO2005]

ineg.src and inot.src have two possible implementations (size versus speed optimized), which is why I have an if 1 there.

Although the size optimized implementation mostly just adds a push/pop de to ineg_fast.src and inot_fast.src, so no knowledge would be lost if they are removed.

[mateoconlechuga]

Then it should be a define to choose size vs speed not some unknown modifier

[mateoconlechuga]

Why did you remove it????

[ZERICO2005]

I removed the size optimized versions of __ineg and __inot. Since a better way to size optimize those routines would be to link to Ti's routines with the PREFER_OS_CRT define

[mateoconlechuga]

Unless the user doesn't have a CE OS

[ZERICO2005]

I also figure that __inot and __ineg are likely the most commonly called routines, and that saving 2 bytes is not really worth it. Having a size optimized version would be better suited towards large and uncommon routines, where something on the order of 20 bytes could be saved for example

[adriweb]

this is just moving files and adding documentation now, so it's fine as CI passes.