[coreboot] Build failure, build log dont link in a proper way

[h42 at memeware.net]

I cloned today the fresh code on a new machine. I first installed the 
dependencies listed here https://www.coreboot.org/Build_HOWTO and then i 
liked to build the whole build gcc for all platforms. I ran 'make 
crossgcc CPUS=6' in the fresh coreboot cloned directory.

Error:
Building GCC v8.1.0 for target ... failed. Check 
'build-riscv64-elf-GCC/build.log'.
Makefile:26: recipe for target 'build_gcc' failed
make[3]: *** [build_gcc] Error 1
Makefile:63: recipe for target 'build-riscv' failed
make[2]: *** [build-riscv] Error 2
Makefile:16: recipe for target 'all_without_gdb' failed
make[1]: *** [all_without_gdb] Error 2
util/crossgcc/Makefile.inc:37: recipe for target 'crossgcc' failed
make: *** [crossgcc] Error 2


I than ran 'cat build-riscv64-elf-GCC/build.log' but that file dont 
exist.

Maybe its somewhere else. When i build the crossgcc in the main 
directory of the project and then it tells me to look into a file, the 
file should be linked properly so that i can run in the same directory i 
am building in a 'cat' command.