chibicc is the simplest/tiniest/hackable/readable c11 compiler in the
world that can build projects like python but goes 2x slower than gcc
with 2x the code size, because it doesn't optimize or color registers
although it can compile code at 5x the speed and could be even faster
which is great, considering it's a 220kb αcτµαlly pδrταblε εxεcµταblε

local enhancements

- support dce
- support gnu asm
- support __int128
- support _Static_assert
- support __vector_size__
- support __builtin_add_overflow, etc.
- support __builtin_memcpy, strlen, strpbrk, etc.
- support __builtin_constant_p, __builtin_likely, etc.
- support __builtin_isunordered, __builtin_islessgreater, etc.
- support __builtin_ctz, __builtin_bswap, __builtin_popcount, etc.
- support __force_align_arg_pointer__, __no_caller_saved_registers__, etc.
- support __constructor__, __section__, __cold__, -ffunction-sections, etc.
- support building -x assembler-with-cpp a.k.a. .S files
- support profiling w/ -mcount / -mfentry / -mnop-mcount
- improve error messages to trace macro expansions
- reduce #lines of generated assembly by a third
- reduce #bytes of generated binary by a third
- report divide errors in constexprs

local bug fixes

- allow casted values to be lvalues
- permit remainder operator in constexprs
- permit parentheses around string-initializer
- fix 64-bit bug in generated code for struct bitfields
- fix struct_designator() so it won't crash on anonymous union members
- fix bug where last statement in statement expression couldn't have label
- print_tokens (chibicc -E) now works in the case of adjacent string literals
- make enums unsigned (like gcc) so we don't suffer the msvc enum bitfield bug

local changes

- use tabs in generated output
- parse javadoc-style markdown comments
- don't fold backslash newline in comments
- generated code no longer assumes red zone
- emit .size directives for function definitions
- use fisttp long double conversions if built w/ -msse3
