Add hooks header

With macros for declaring hooks in header, in code, actually hooking and
calling the originals
Also with CL_CreateMove hooked

src/include/hooks.h

@@ -0,0 +1,65 @@
+
+#ifndef _HOOKS_H
+#define _HOOKS_H
+
+/*----------------------------------------------------------------------------*/
+
+#include "sdk.h"
+
+/*
+ * Table of prefixes:
+ *   prefix | meaning
+ *   -------+----------------------------
+ *   *_t    | typedef (function type)
+ *   h_*    | hook function (ours)
+ *   ho_*   | hook original (ptr to orig)
+ *
+ *
+ * DECL_HOOK_EXTERN: Version for the header. typedef's the function pointer with
+ * the return type, name and args. Example:
+ *
+ *   DECL_HOOK_EXTERN(int, test, double, double);
+ *     typedef int (*test_t)(double, double);
+ *     extern test_t ho_test;                  // Original
+ *     int h_test(double, double);             // Our func
+ *
+ *
+ * DECL_HOOK: Macro for declaring the global function pointer for the original
+ * in the source file. Example:
+ *
+ *   DECL_HOOK(test);
+ *     test_t ho_test = NULL;       // Original
+ *
+ *
+ * HOOK: Macro for storing the original function ptr of an interface and hooking
+ * our own. Example:
+ *
+ *   HOOK(gp_client, CL_CreateMove);
+ *     ho_CL_CreateMove = gp_client->CL_CreateMove;     // Original
+ *     gp_client->CL_CreateMove = h_CL_CreateMove;      // Our func
+ *
+ *
+ * ORIGINAL: Macro for calling the original function. Example:
+ *
+ *   ORIGINAL(CL_CreateMove, frametime, cmd, active);
+ *     ho_CL_CreateMove(frametime, cmd, active);        // Original
+ */
+#define DECL_HOOK_EXTERN(type, name, ...)  \
+    typedef type (*name##_t)(__VA_ARGS__); \
+    extern name##_t ho_##name;             \
+    type h_##name(__VA_ARGS__);
+
+#define DECL_HOOK(name) name##_t ho_##name = NULL;
+
+#define HOOK(interface, name)          \
+    ho_##name       = interface->name; \
+    interface->name = h_##name;
+
+#define ORIGINAL(name, ...) ho_##name(__VA_ARGS__);
+
+/*----------------------------------------------------------------------------*/
+
+bool hooks_init(void);
+DECL_HOOK_EXTERN(void, CL_CreateMove, float, usercmd_t*, int);
+
+#endif /* _HOOKS_H */