r270991, r271045:
Enhancements related to compiling FDT data...
- Use proper include path for dtc as well as cpp.
- Call cpp with -P to avoid printing line markings.
- Allow FDT_DTS_FILE to be a list, either in the makedtb target, or in a
kernel config file.
- Add the dts include directory to the -I list when doing arm builds.
- Invoke make_dtb with MACHINE defined for cross building friendliness.
- Allow the make_dtb script to work outside of a "make buildkernel"
context by setting MACHINE from uname -m if it's not set already.
- Use sh -c '...' to launch the dtb build scripts with env prepended,
otherwise it tries to treat the env var stuff as a script file name.
8f1520bd13