Begin converting os.Errno to be a nil-able type as a transition period

core/os/os_essence.odin

@@ -2,54 +2,54 @@ package os
 
 import "core:sys/es"
 
-Handle :: distinct int;
-Errno :: distinct int;
+Handle :: distinct int
+_Platform_Error :: enum i32 {NONE}
 
-ERROR_NONE :: (Errno) (es.SUCCESS);
+ERROR_NONE :: Errno(es.SUCCESS)
 
-O_RDONLY :: 0x1;
-O_WRONLY :: 0x2;
-O_CREATE :: 0x4;
-O_TRUNC  :: 0x8;
+O_RDONLY :: 0x1
+O_WRONLY :: 0x2
+O_CREATE :: 0x4
+O_TRUNC  :: 0x8
 
-stderr : Handle = 0; 
+stderr : Handle = 0
 
 current_thread_id :: proc "contextless" () -> int {
-	return (int) (es.ThreadGetID(es.CURRENT_THREAD));
+	return (int) (es.ThreadGetID(es.CURRENT_THREAD))
 }
 
 heap_alloc :: proc(size: int, zero_memory := true) -> rawptr {
-	return es.HeapAllocate(size, zero_memory);
+	return es.HeapAllocate(size, zero_memory)
 }
 
 heap_free :: proc(ptr: rawptr) {
-	es.HeapFree(ptr);
+	es.HeapFree(ptr)
 }
 
 heap_resize :: proc(ptr: rawptr, new_size: int) -> rawptr {
-	return es.HeapReallocate(ptr, new_size, false);
+	return es.HeapReallocate(ptr, new_size, false)
 }
 
 open :: proc(path: string, flags: int = O_RDONLY, mode: int = 0) -> (Handle, Errno) {
-	return (Handle) (0), (Errno) (1);
+	return (Handle) (0), (Errno) (1)
 }
 
 close :: proc(fd: Handle) -> Errno {
-	return (Errno) (1);
+	return (Errno) (1)
 }
 
 file_size :: proc(fd: Handle) -> (i64, Errno) {
-	return (i64) (0), (Errno) (1);
+	return (i64) (0), (Errno) (1)
 }
 
 read :: proc(fd: Handle, data: []byte) -> (int, Errno) {
-	return (int) (0), (Errno) (1);
+	return (int) (0), (Errno) (1)
 }
 
 write :: proc(fd: Handle, data: []u8) -> (int, Errno) {
-	return (int) (0), (Errno) (1);
+	return (int) (0), (Errno) (1)
 }
 
 seek :: proc(fd: Handle, offset: i64, whence: int) -> (i64, Errno) {
-	return (i64) (0), (Errno) (1);
+	return (i64) (0), (Errno) (1)
 }