SYS_ARCH_PROTECT macro

SYS_ARCH_PROTECT Perform a "fast" protect. This could be implemented by disabling interrupts for an embedded system or by using a semaphore or mutex. The implementation should allow calling SYS_ARCH_PROTECT when already protected. The old protection level is returned in the variable "lev". This macro will default to calling the sys_arch_protect() function which should be implemented in sys_arch.c. If a particular port needs a different implementation, then this macro may be defined in sys_arch.h