Set a var param_type to double if it's a float of size 8
Added ORC_TARGET_DOUBLE_IN_TWO_REGISTERS target flag
Handle float/double logic in orc_compiler_allocate_register()
mips: add ORC_TARGET_DOUBLE_IN_TWO_REGISTERS to default flags
mips: accept variables of 8 bytes
mips: added _emit() for ldc1, sdc1, mthc1 and mfhc1
mips: implemented loadq and storeq for doubles
mips: added _emit() for add.d
mips: implemented addd