First stage of dynamic recompiler rewrite.

Basic IR generation calls C implementation of all instructions.
Backend generation implemented for x86, x86-64, ARM and ARM64.

src/codegen_backend_arm64_defs.h

@@ -0,0 +1,72 @@
+#define REG_W0   0
+#define REG_W1   1
+#define REG_W2   2
+#define REG_W3   3
+#define REG_W4   4
+#define REG_W5   5
+#define REG_W6   6
+#define REG_W7   7
+#define REG_W8   8
+#define REG_W9   9
+#define REG_W10 10
+#define REG_W11 11
+#define REG_W12 12
+#define REG_W13 13
+#define REG_W14 14
+#define REG_W15 15
+#define REG_W16 16
+#define REG_W17 17
+#define REG_W18 18
+#define REG_W19 19
+#define REG_W20 20
+#define REG_W21 21
+#define REG_W22 22
+#define REG_W23 23
+#define REG_W24 24
+#define REG_W25 25
+#define REG_W26 26
+#define REG_W27 27
+#define REG_W28 28
+#define REG_W29 29
+#define REG_W30 30
+
+#define REG_X0   0
+#define REG_X1   1
+#define REG_X2   2
+#define REG_X3   3
+#define REG_X4   4
+#define REG_X5   5
+#define REG_X6   6
+#define REG_X7   7
+#define REG_X8   8
+#define REG_X9   9
+#define REG_X10 10
+#define REG_X11 11
+#define REG_X12 12
+#define REG_X13 13
+#define REG_X14 14
+#define REG_X15 15
+#define REG_X16 16
+#define REG_X17 17
+#define REG_X18 18
+#define REG_X19 19
+#define REG_X20 20
+#define REG_X21 21
+#define REG_X22 22
+#define REG_X23 23
+#define REG_X24 24
+#define REG_X25 25
+#define REG_X26 26
+#define REG_X27 27
+#define REG_X28 28
+#define REG_X29 29
+#define REG_X30 30
+
+#define REG_SP  31
+
+#define REG_ARG0 REG_X0
+#define REG_ARG1 REG_X1
+#define REG_ARG2 REG_X2
+#define REG_ARG3 REG_X3
+
+#define REG_CPUSTATE REG_X29