Code should not rely on the contents of local variables set before
setjmp() after the longjmp() returns. In this case, it was notpossible
to reset events after the return. But analysis determined that the
longjmp() should always returns to the same stack frame. Thus local
variables should be preserved. The warning was disabled.
This case was not addressed by adding the "returns_twice" attribute
to setjmp() in setjmp.h.
Updates #5364.
Fixed many warnings for unused parameters. Some cases were
a simple matter of adding "(void) param" at the beginning
of the function, while others required ensuring that addition
was inside the proper conditional section. Found with GCC's
warning -Wunused-paramter.
