* check/cva_list.c: New file implementing a test to ensure
the value returned by jit_va_start is a valid C va_list.
* check/va_list.ok: New simple helper file, as now the
va_list.tst test is enabled.
* check/va_list.tst: Rewritten for an extensive variadic
jit functions test.
* check/Makefile.am: Update for the new tests.
* lib/jit_arm-cpu.c, lib/jit_arm-swf.c, lib/jit_arm-vfp.c,
lib/jit_arm.c: Correct broken software float in a previous
commit. Note that the hard float abi implementation is known
broken at this time, for special cases involving variadic
functions, and should be corrected next.
lib/jit_x86-cpu.c, lib/jit_x86-sz.c, lib/jit_x86.c: Correct
the jit_va_list_t semantics to match C va_list.
