main.v: fix broken thirdparty dependencies

compiler/main.v

@@ -84,6 +84,7 @@ mut:
 	out_name   string // "program.exe"
 	is_prod    bool // use "-O2" and skip printlns (TODO I don't thik many people want printlns to disappear in prod buidls)
 	is_repl    bool
+	vroot      string
 }
 
 fn main() {
@@ -825,6 +826,7 @@ fn new_v(args[]string) *V {
 		build_mode: build_mode
 		is_run: args.contains('run')
 		is_repl: args.contains('-repl')
+		vroot: lang_dir
 	}
 }
 

compiler/parser.v

@@ -70,6 +70,7 @@ mut:
 	calling_c      bool
 	cur_fn         *Fn
 	returns        bool
+	vroot          string
 }
 
 const (
@@ -99,6 +100,7 @@ fn (c mut V) new_parser(path string, run Pass) Parser {
 		build_mode: c.build_mode
 		is_repl: c.is_repl
 		run: run
+		vroot: c.vroot
 	}
 	p.next()
 	// p.scanner.debug_tokens()
@@ -2605,7 +2607,7 @@ fn (p mut Parser) chash() {
 			pos := flag.index(' ')
 			flag = flag.right(pos)
 		}
-		flag = flag.trim_space()
+		flag = flag.trim_space().replace('@VROOT', p.vroot)
 		if p.table.flags.contains(flag) {
 			return
 		}