rename constructor
update codegen IR
add new files
refine module declaration
add SimplifyAST prototype
update LLIR definition
rename SimplifyAST => NormalizeAST
symbol only contains local declarations
remove semantic AST normalization passes
remove type synonym declaration from symbol table
- this causes some mysterious error upon redeclaration though, like
    typedef int a; int main() { return a; }

    `a` was treated as non-existence during TypeCheck phase
remove some TODOs and fix abused type synonym detection
merge case-of in SymTable
Add: some random note
makefile now detects cygwin

perhaps
update lovely Makefile
Add: show some AsmIRs
rename files
Edit: syscall is rtype
update potential LLIR
Added: nothing