Some pthread_ function can't be found in by gollvm

[JX Zhang]

I met some problem about pthread.

I wrote a cgo demo which use some pthread_* function, but it compile failed

ccode.c

```

# include <stdio.h>

# include "ccode.h"

# include <pthread.h>

int try_pthread(){

pthread_t id;

int ret, i = 0;

ret = pthread_create(&id,NULL,(void *)thread,NULL);

for(i=0;i<=5;i++)

printf("This is main thread %d\n",i);

pthread_join(id,NULL);

pthread_once(id, NULL);

return 0;

}

void thread()

{

int i=0;

for(i=0;i<=5;i++)

printf("this is thread %d\n",i);

}

```

main.go

```

package main

/*

#cgo CFLAGS: -I./

#cgo LDFLAGS: -L./

#include "ccode.h"

*/

import "C"

func main() {

_ = C.try_pthread()

}

```

the `pthread_create` can be searched, but the other two functions report this:

ccode.c:11: error: undefined reference to 'pthread_join'

ccode.c:12: error: undefined reference to 'pthread_once'

[JX Zhang]

 ✘~/workspace/gowork/src/pthread $  go build .

# pthread

ccode.c:12:15: warning: incompatible integer to pointer conversion passing 'pthread_t' (aka 'unsigned long') to parameter of type 'pthread_once_t *' (aka 'int *') [-Wint-conversion]

/usr/include/pthread.h:495:42: note: passing argument to parameter '__once_control' here

ccode.c:12:23: warning: null passed to a callee that requires a non-null argument [-Wnonnull]

# pthread

ccode.c:11: error: undefined reference to 'pthread_join'

ccode.c:12: error: undefined reference to 'pthread_once'

/usr/lib/gcc/x86_64-linux-gnu/8/libgcc.a(generic-morestack-thread.o):function __wrap_pthread_create: error: undefined reference to 'pthread_once'

--------------------------------

Make  the pthread_join and pthread_once as comments and recompile the file

```bash

~/workspace/gowork/src/pthread $ ldd main

linux-vdso.so.1 (0x00007ffc58db4000)

libgo.so.13git => /home/jxzhang/.local/gollvm/lib64/libgo.so.13git (0x00007fc599db0000)

libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007fc599a12000)

libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007fc5997fa000)

libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fc599409000)

/lib64/ld-linux-x86-64.so.2 (0x00007fc59b6cb000)

libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007fc5991ea000)

 ~/workspace/gowork/src/pthread $ nm /home/jxzhang/.local/gollvm/lib64/libgo.so.13git | grep -E "pthread_create|pthread_join|pthread_once"

                 w pthread_create

                 w pthread_once

0000000001089d70 t __wrap_pthread_create

 ~/workspace/gowork/src/pthread $ nm /lib/x86_64-linux-gnu/libpthread.so.0 | grep -E "pthread_create|pthread_join|pthread_once"

000000000000f9b0 t __GI___pthread_once

00000000000079b0 t __pthread_create_2_1

00000000000079b0 T pthread_create@@GLIBC_2.2.5

0000000000008b50 t __pthread_join

0000000000008b50 W pthread_join

000000000000f9b0 T __pthread_once

000000000000f9b0 W pthread_once

000000000000f850 t __pthread_once_slow

```

[JX Zhang]

Has anyone ever encountered this problem？