I work on centos 6.8. gcc 5.3 and binutilus is not installed in the standard path. When I use scons, it show:
??scons: Reading SConscript files ...
scons version: 3.0.0
python version: 2 7 11 'final' 0
Checking whether the C compiler works... yes
Checking whether the C++ compiler works... yes
Checking that the C++ compiler can link a C++ program... yes
Checking if C++ compiler "g++" is GCC... yes
Checking if C compiler "gcc" is GCC... yes
Detected a x86_64 processor
Checking if target OS linux is supported by the toolchain... yes
Checking if C compiler is GCC 5.3.0 or newer...no
Checking if C++ compiler is GCC 5.3.0 or newer...no
ERROR: Refusing to build with compiler that does not meet requirements
See /root/coding/mongo-master/build/scons/config.log for details??

And If I add CC and CXX option to scons, it will find the gcc/g++, but still cannot find corrresonding custom as and ld (system as and ld cannot work).

Please help, how can add custom linker to scons ?