Tried to compile opencl kernel, got close but not quite

Clang Frontend
1

I have very simple opencl kernel and wanted to compile it using amdgpu as target:
https://llvm.org/docs/AMDGPUUsage.html#target-triples

file:

#include <CL/cl.h>
#include <stdio.h>

kernel void kernelfcn(      global uint *dev_c,   global uint * dev_a,  global uint * dev_b)
{
  uint tid = get__id(0);
 *dev_c = 100;
 *dev_a = 200;
}

But it errors out with that:

clang --target=amdgcn-amd-amdhsa -c p25k.c -o p25k.o
In file included from p25k.c:1:
In file included from /usr/local/include/CL/cl.h:33:
In file included from /usr/local/include/CL/cl_platform.h:224:
In file included from /opt/rocm-4.1.0/llvm/lib/clang/12.0.0/include/stdint.h:52:
/usr/include/stdint.h:26:10: fatal error: 'bits/libc-header-start.h' file not found
#include <bits/libc-header-start.h>
         ^~~~~~~~~~~~~~~~~~~~~~~~~~
1 error generated.
2

You may need gcc-multilib package.

ref: c - "fatal error: bits/libc-header-start.h: No such file or directory" while compiling HTK - Stack Overflow

3

Yes indeed, however no I got following error:

sudo apt-get install gcc-multilib g+±multilib -y

p25k.c:4:1: error: unknown type name ‘kernel’
kernel void kernelfcn( global uint *dev_c, global uint * dev_a, global uint * dev_b)
^
p25k.c:4:29: error: unknown type name ‘global’
kernel void kernelfcn( global uint *dev_c, global uint * dev_a, global uint * dev_b)
^
p25k.c:4:41: error: expected ‘)’
kernel void kernelfcn( global uint *dev_c, global uint * dev_a, global uint * dev_b)
^
p25k.c:4:22: note: to match this ‘(’
kernel void kernelfcn( global uint *dev_c, global uint * dev_a, global uint * dev_b)
^
p25k.c:7:3: error: use of undeclared identifier ‘dev_c’
*dev_c = 100;
^
p25k.c:8:3: error: use of undeclared identifier ‘dev_a’
*dev_a = 200;
^
5 errors generated.