Add the new ccall test case to test interleaved C and jit function calls

* check/cccall.c, check/ccall.ok: New test case to validate
	interleaved calls from/to C code and jit.

	* check/Makefile.am: Update for the new ccall test case.

	* include/lightning.h, lib/lightning.c: Add the new jit_address
	call that returns the real/final address of a "note" in the
	generated jit. It requires a jit_node_t as returned by the
	jit_note call, and is only valid after calling jit_emit.
	  Add an intermediate solution to properly handle arm
	soft and softfp modes that move a double to an integer register
	pair. Currently it just adds extra tests for the condition,
	but the proper solution should be to have extra lightning
	codes for these conditions, codes which should be only used
	by the backends that need it, and merged with the existing
	jit_pusharg*_{f,d}.

	* include/lightning/jit_private.h: Add new jit_state_t flag
	to know it finished jit_emit, so that calls to jit_address
	are valid.

	* lib/jit_mips.c: Correct abi implementation so that the
	new ccall test case pass. Major problem was using
	_jit->function.self.arg{i,f} as boolean values, but that
	would cause lightning.c:patch_registers() to incorrectly
	assume only one register was used as argument when calling
	jit_regarg_p(); _jit->function.self.arg{i,f} must be the
	number of registers used as arguments (in all backends).

	* lib/jit_x86.c: Add workaround, by marking %rax as used,
	to a special condition, when running out of registers and the
	allocator trying to spill and reload %rax, but %rax was used
	as a pointer to a function, what would cause the reload to
	destroy the return value. This condition can be better
	generalized, but the current solution is good enough.

	* include/lightning/jit_ppc.h, lib/jit_ppc-cpu.c, lib/jit_ppc.c:
	Rewrite logic to handle arguments, as the original code was
	written based on a SysV pdf about the generic powerpc ABI,
	what did "invent" a new abi for the previous test cases, but
	failed in the new ccall test in Darwin PPC. Now it properly
	handles 13 float registers for arguments, as well as proper
	computation of stack offsets when running out of registers
	for arguments.

include/lightning.h

@@ -728,6 +728,8 @@ extern void finish_jit(void);
 
 extern jit_state_t *jit_new_state(void);
 
+#define jit_address(node)	_jit_address(_jit, node)
+extern jit_pointer_t _jit_address(jit_state_t*, jit_node_t*);
 extern jit_node_t *_jit_data(jit_state_t*, jit_pointer_t, jit_word_t);
 extern jit_node_t *_jit_note(jit_state_t*, jit_pointer_t);