PREFIXVAR is defined in cppdefaults.c as well which shows up as error
when LTO is enabled to build gcc, therefore rename the one instance to PREFIXVAR1
(From OE-Core rev: 984da023a595a10ae62d4fc2a1f2fe96c4701223)
Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>