Fix type patching

[cpunion]

Fix #877

package main

import (
	"io"
	"os"
	"sync"
	"unsafe"

	llsync "github.com/goplus/llgo/c/pthread/sync"
)

type L struct {
	mu sync.Mutex
	s  string
	i  int
	w  io.Writer
}

func main() {
	l := &L{s: "hello", i: 123, w: os.Stdout}
	println("sizeof(L):", unsafe.Sizeof(L{}))
	println("sizeof(sync.Mutex):", unsafe.Sizeof(sync.Mutex{}))
	println("sizeof(llsync.Mutex):", unsafe.Sizeof(llsync.Mutex{}))
	println("l:", l, "l.s:", l.s, "l.i:", l.i, "l.w:", l.w)
	l.mu.Lock()
	println("locked")
	println("l:", l, "l.s:", l.s, "l.i:", l.i, "l.w:", l.w)
	l.w.Write([]byte(l.s))
	l.w.Write([]byte("\n"))
	l.mu.Unlock()
}

Outputs on macOS arm64:

sizeof(L): 48
sizeof(sync.Mutex): 8
sizeof(llsync.Mutex): 64
l: 0x102649a10 l.s: hello l.i: 123 l.w: (0x10264e8d0,0x10264e990)
locked
l: 0x102649a10 l.s: hello l.i: 123 l.w: (0x10264e8d0,0x10264e990)
hello

Outputs on Ubuntu arm64:

l: 0x4000163360 l.out: (0x84de58,0x4000120010)
sizeof(L): 48
sizeof(sync.Mutex): 8
sizeof(llsync.Mutex): 48
l: 0xe6b592ab7f60 l.s: hello l.i: 123 l.w: (0xe6b592aa17b0,0xe6b592aa1870)
locked
l: 0xe6b592ab7f60 l.s: hello l.i: 123 l.w: (0xe6b592aa17b0,0xe6b592aa1870)
hello

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.54%. Comparing base (2f5c033) to head (3f795e4).
Report is 3 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #879   +/-   ##
=======================================
  Coverage   95.54%   95.54%           
=======================================
  Files          22       22           
  Lines        6237     6246    +9     
=======================================
+ Hits         5959     5968    +9     
  Misses        246      246           
  Partials       32       32           

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