[LLVMdev] README: Build Environment Changes

[Vladimir Merzliakov]

Next problem detected by nighttest:

LLVM build fail with errors:

gmake[4]: Entering directory 
`/usr/home/wanderer/pkg/build/llvm/night/build/llvm/projects/Stacker/lib/runtime'
llvm[4]: Compiling stacker_rt.c for Debug build (bytecode)
default/bin/llvm-gcc: not found
gmake[4]: *** 
[/usr/home/wanderer/pkg/build/llvm/night/build/llvm/projects/Stacker/lib/runtime/Debug/stacker_rt.bc] 
Error 1
gmake[4]: Leaving directory 
`/usr/home/wanderer/pkg/build/llvm/night/build/llvm/projects/Stacker/lib/runtime'

Vladimir