GCC build error on FreeBSD 12.1 with LLVM 8.0.1

[Sebastian Huber <sebastian dot huber at embedded-brains dot de>]

Hello,

I tried to build a recent GCC master on FreeBSD 12.1 and it failed with 
a compile error:

$ clang --version
FreeBSD clang version 8.0.1 (tags/RELEASE_801/final 366581) (based on 
LLVM 8.0.1)
Target: x86_64-unknown-freebsd12.1
Thread model: posix
InstalledDir: /usr/bin

../../gnu-mirror-gcc-5bc9d2f5ed4/gcc/analyzer/engine.cc:2965:13: error: 
reinterpret_cast from 'nullptr_t' to 'function *' is not allowed
  v.m_fun = reinterpret_cast<function *> (NULL);
            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../gnu-mirror-gcc-5bc9d2f5ed4/gcc/analyzer/engine.cc:2977:21: error: 
reinterpret_cast from 'nullptr_t' to 'function *' is not allowed
  return v.m_fun == reinterpret_cast<function *> (NULL);
                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This simple test program fails also:

struct function;

function *f(void)
{
  return reinterpret_cast<function *>(nullptr);
}

$ clang -c test.cc
test.cc:5:10: error: reinterpret_cast from 'nullptr_t' to 'function *' 
is not allowed
  return reinterpret_cast<function *>(nullptr);
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1 error generated.

I was able to build the GCC master on January 2nd 2020. Does this look 
like an LLVM 8.0.1 issue or a GCC issue?