incorporate Tony's patches:
+ c/src/lib/libc/support/generic/malloc.c did not initialize the sbrk amount + _Thread_Handler in c/src/exec/rtems/thread.c left a window during the begin extension which could result in a context switch
+ c/src/lib/libc/support/generic/malloc.c did not initialize the
sbrk amount
+ _Thread_Handler in c/src/exec/rtems/thread.c left a window
during the begin extension which could result in a context switch
fixed places which did not correctly distinguish between an CPU_isr and a CPU_isr_entry.