compiler: restore support for --enable-globals flag, and add tests.

cmd/v/v.v

@@ -143,6 +143,9 @@ fn parse_args(args []string) (&pref.Preferences, string) {
 			'-shared' {
 				res.is_shared = true
 			}
+			'--enable-globals' {
+				res.enable_globals = true
+			}
 			'-autofree' {
 				res.autofree = true
 			}

vlib/v/checker/checker_test.v

@@ -1,10 +1,6 @@
 import os
 import term
 
-fn clean_line_endings(s string) string {
-	return s.trim_space().replace(' \n', '\n').replace(' \r\n', '\n').replace('\r\n', '\n').trim('\n')
-}
-
 fn test_all() {
 	mut total_errors := 0
 	vexe := os.getenv('VEXE')
@@ -21,17 +17,24 @@ fn test_all() {
 	}
 	tests.sort()
 	for test in tests {
+		// -prod so that warns are errors
+		total_errors += check_path(vexe, dir, test, '-prod', '.out')
+	}
+	total_errors += check_path(vexe, dir, 'globals_error.vv', '--enable-globals run', '.run.out')
+	assert total_errors == 0
+}
+
+fn check_path(vexe, dir, test, voptions, result_extension string) int {
 	path := os.join_path(dir, test).replace('\\', '/')
 	program := path.replace('.vv', '.v')
 	print(program + ' ')
 	os.cp(path, program) or {
 		panic(err)
 	}
-		// -prod so that warn are errors
-		res := os.exec('$vexe -prod $program') or {
+	res := os.exec('$vexe $voptions $program') or {
 		panic(err)
 	}
-		mut expected := os.read_file(program.replace('.v', '') + '.out') or {
+	mut expected := os.read_file(program.replace('.v', '') + result_extension) or {
 		panic(err)
 	}
 	expected = clean_line_endings(expected)
@@ -45,11 +48,14 @@ fn test_all() {
 		println('found:')
 		println(found)
 		println('============\n')
-			total_errors++
+		return 1
 	} else {
 		println(term.green('OK'))
-			os.rm( program )
+		os.rm(program)
 	}
-	}
-	assert total_errors == 0
+	return 0
+}
+
+fn clean_line_endings(s string) string {
+	return s.trim_space().replace(' \n', '\n').replace(' \r\n', '\n').replace('\r\n', '\n').trim('\n')
 }

vlib/v/checker/tests/globals_error.out

@@ -0,0 +1,6 @@
+vlib/v/checker/tests/globals_error.v:2:1: error: use `v --enable-globals ...` to enable globals
+    1 |
+    2 | __global rfcnt int
+      | ~~~~~~~~
+    3 |
+    4 | fn abc(){

vlib/v/checker/tests/globals_error.run.out

@@ -0,0 +1 @@
+rfcnt: 2

vlib/v/checker/tests/globals_error.vv

@@ -0,0 +1,12 @@
+
+__global rfcnt int
+
+fn abc(){
+	rfcnt = 2
+}
+
+fn main(){
+	rfcnt = 1
+	abc()
+	println('rfcnt: $rfcnt')
+}

vlib/v/pref/default.v

@@ -70,7 +70,6 @@ pub fn (mut p Preferences) fill_with_defaults() {
 			}
 		}
 	}
-	p.enable_globals = false
 }
 
 fn default_c_compiler() string {