D lexer, parser, and ImportC parser are now standalone

[Andrej Mitrovic]

On Thursday, 13 April 2023 at 14:27:33 UTC, Andrej Mitrovic wrote:
> And yes now I realize this isn't supposed to be used with just 
> a regular D install, as it needs to import into DMD modules 
> which aren't part of the release package.

```
$ dmd -I/c/dev/dmd/compiler/src/ app.d
app.d(17): Error: none of the overloads of `this` are callable 
using argument types `(string, immutable(char)*, int, ulong, int, 
int)`
/c/dev/dmd/compiler/src/dmd/lexer.d(111):        Candidates are: 
`dmd.lexer.Lexer.this(const(char)* filename, const(char)* base, 
ulong begoffset, ulong endoffset, bool doDocComment, bool 
commentToken, ErrorSink errorSink, const(char)[] vendor = "DLF", 
uint versionNumber = 1u)`
/c/dev/dmd/compiler/src/dmd/lexer.d(170):                        
`dmd.lexer.Lexer.this(const(char)* filename, const(char)* base, 
ulong begoffset, ulong endoffset, bool doDocComment, bool 
commentToken, bool whitespaceToken, ErrorSink errorSink)`
/c/dev/dmd/compiler/src/dmd/lexer.d(182):                        
`dmd.lexer.Lexer.this(ErrorSink errorSink)`
```

I'll submit to bugzilla.