syscall: group WASI consts by purpose

Signed-off-by: Roman Volosatovs <roman@profian.com>

src/syscall/syscall_libc_wasi.go

@@ -51,9 +51,10 @@ const (
 
 const (
 	__WASI_OFLAGS_CREAT = 1
-	__WASI_FDFLAGS_APPEND = 1
 	__WASI_OFLAGS_EXCL  = 4
 	__WASI_OFLAGS_TRUNC = 8
+
+	__WASI_FDFLAGS_APPEND   = 1
 	__WASI_FDFLAGS_SYNC     = 16
 
 	O_RDONLY = 0x04000000
@@ -62,8 +63,9 @@ const (
 
 	O_CREAT = __WASI_OFLAGS_CREAT << 12
 	O_TRUNC = __WASI_OFLAGS_TRUNC << 12
-	O_APPEND = __WASI_FDFLAGS_APPEND
 	O_EXCL  = __WASI_OFLAGS_EXCL << 12
+
+	O_APPEND   = __WASI_FDFLAGS_APPEND
 	O_SYNC     = __WASI_FDFLAGS_SYNC
 
 	O_CLOEXEC = 0