armstubs: Define the new symbols use in Makefile
The tools repository renamed the CC, LD etc symbols to CC7, LD7 etc.
See:
@@ -11,6 +11,10 @@ COMPATIBLE_MACHINE = "^rpi$"
S = "${RPITOOLS_S}/armstubs"
+export CC7="${CC}"
+export LD7="${LD}"
+export OBJCOPY7="${OBJCOPY}"
+export OBJDUMP7="${OBJDUMP}"
export CC8="${CC}"
export LD8="${LD}"
export OBJCOPY8="${OBJCOPY}"
