all: bare metal support (fix -freestanding) (#9624)

vlib/builtin/linux_bare/old/.checks/structs/structs.v

@@ -0,0 +1,42 @@
+module main
+import forkedtest
+
+struct SimpleEmptyStruct{
+}
+
+struct NonEmptyStruct{
+  x int
+  y int
+  z int
+}
+
+fn check_simple_empty_struct(){  
+  s := SimpleEmptyStruct{}
+  addr_s := &s
+  str_addr_s := ptr_str( addr_s )
+  assert !isnil(addr_s)
+  assert str_addr_s.len > 3
+  println(str_addr_s)
+}
+
+fn check_non_empty_struct(){  
+  a := NonEmptyStruct{1,2,3}
+  b := NonEmptyStruct{4,5,6}
+  assert sizeof(NonEmptyStruct) > 0
+  assert sizeof(SimpleEmptyStruct) < sizeof(NonEmptyStruct)
+  assert a.x == 1
+  assert a.y == 2
+  assert a.z == 3
+  assert b.x + b.y + b.z == 15
+  assert ptr_str(&a) != ptr_str(&b)
+  println('sizeof SimpleEmptyStruct:' + i64_str( sizeof(SimpleEmptyStruct) , 10 ))
+  println('sizeof NonEmptyStruct:' + i64_str( sizeof(NonEmptyStruct) , 10 ))
+}
+
+fn main(){
+	mut fails := 0
+	fails += forkedtest.normal_run(check_simple_empty_struct, "check_simple_empty_struct")
+	fails += forkedtest.normal_run(check_non_empty_struct,    "check_non_empty_struct")
+	assert fails == 0
+	sys_exit(0)
+}