[LLVM-521] LLD and taking the address of an ifunc
Went through the possible combinations (pic, pie, non-pic, exec,
shared,...) found one relocation that gcc uses that clang doesn't,
hence mc and LLD don't support. Raised upstream pr. Also found that
clang's code-sequence for -fpie doesn't seem to
Progress:
* VIRT-65 [QEMU upstream maintainership]
+ some code review, and another arm pull-request (including
RTH's pointer auth work)
+ sent patch fixing a bug in the gdbstub memory access path that
meant it was always making accesses as NonSecure even if the
guest CPU was curren
