Fix on head by setting LLD_UNSAFE:

ld: error: /usr/lib/libpmc.so: undefined reference to std::1::basic_string_common<true>::throw_length_error() const
ld: error: /usr/lib/libpmc.so: undefined reference to std::1::basic_string<char, std::1::char_traits<char>, std::1::allocator<char> >::append(char const*, unsigned long)
cc: error: linker command failed with exit code 1 (use -v to see invocation)

Since I'm here, add USES=gl.