subdir-ccflags-y, subdir-asflags-y
The two flags listed above are similar to ccflags-y and as-falgs-y.
The difference is that the subdir- variants has effect for the kbuild
- file where they are present and all subdirectories.
+ file where tey are present and all subdirectories.
Options specified using subdir-* are added to the commandline before
the options specified using the non-subdir variants.