Cross-compiler openpli4&5 broken

Hi, i build a full image for my solo2 from this branch

git clone git://github.com/OpenPLi/openpli-oe-core
cd openpli-oe-core
git checkout master-for-gcc5
git pull

But in my opinion the gcc compiler is broken (or missing something)

#include <stdio.h> 
int main (void) 
{
printf ("Hello, world!\n"); 
return 0; 
}

 /home/davide/openpli_4.0/openpli-oe-core/build/tmp/sysroots/x86_64-linux/usr/bin/mipsel-oe-linux/mipsel-oe-linux-gcc -Wall hello.c -o hello
hello.c:1:20: fatal error: stdio.h: No such file or directory
#include <stdio.h> 
^
compilation terminated.

Same error with openpli 5 environment

Why? With a cross-compiler from master branch i was able to cross-compile...

P.S. i known that is (probably) a nonsense because with bitbake i can compile everything but this is a different thing and i should like to known what happens with a new environment. So please don' t ask to me "use bitbake".

Thanks