Modified for supporting ARM Thumb

Tried to compile libHoard for a Cubieboard which has an A10 ARM (armv7). That resulted in some compilation error due to that ARM Thumb didn't support the used cmp operation in spinlock.h.
After som Googling I came up with an alternative for this type of ARM and testing show it works. In libHoard I alsoa added "-fPIC" to the target GENERIC_GCC_COMPILE, but I've only done that locally so far.
The benchmarks (after removing the printf's) didn't show any significant difference except for linux-scalability.

BR

Daniel