The self-hosted compiler reads headers with boot/cimport.fch and compiles calls to C
functions (variadics, char* as str, C's default promotions), enum and #define
constants, extern variables like stdout, C structs laid out as C laid them (padding
and fixed arrays, by pointer), .ptr of a str or array, ptr(x) and int(ptr). link
"lib" asks pkg-config, link "x.c" compiles the file along.
cimport and c_pointers pass. Not yet: structs by value (the calling convention) and
addr(fn) for C callbacks, which is also what stops it building itself.
boot.sh now says so when stage 2 can't be made and runs the tests on stage 1.
Reads functions (with variadics and why one is unsupported), enum and #define
constants, extern variables and structs with their layout, the same as
src/cimport.cpp. It calls libclang through Finch's own C import, so compiling
it is what the bootstrap will have to do. Checked with the C++ compiler:
stdio.h gives 90 functions and 347 constants; EOF is -1, stdout is ptr[C.FILE].
