ArmPkg/ArmExceptionLib: make build time define visible to the compiler
ArmPkg/ArmExceptionLib: make build time define visible to the compiler

The global gArmRelocateVectorTable is a build time constant, but due to
its external linkage and lack of constness, the compiler does not see that.
So turn it into a static boolean, and at the same time, make the function
CopyExceptionHandlers() (which is only called if gArmRelocateVectorTable is
set) static as well, so that the compiler can eliminate it completely if
we are using the vector table in place.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <66d3c5fdaeea7ff1f996ad04f2c45e08ab38e2f5@linaro.org>
Reviewed-by: Leif Lindholm <a613079f0455438b29e28a9c5b9eb3779a81a33a@linaro.org>
Reviewed-by: Eugene Cohen <9ca3a9f70b33e046bab2e2acccb982c72f85783a@hp.com>

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