Add header for globals.c

With DECLARE_SYMBOLS and DECLARE_EXTERNS macros
hw extern for hw.so handler
Externs engine and client symbol pointers (and originals)
globals_init function

src/include/globals.h

@@ -0,0 +1,32 @@
+#ifndef _GLOBALS_H
+#define _GLOBALS_H
+
+#include "sdk.h"
+
+/*----------------------------------------------------------------------------*/
+
+/*
+ * prefix | meaning
+ * -------+----------------
+ * gp_*   | global pointer
+ * go_*   | global original
+ */
+#define DECLARE_SYMBOLS(type, name) \
+    type* gp_##name = NULL;         \
+    type go_##name;
+
+#define DECLARE_EXTERNS(type, name) \
+    extern type* gp_##name;         \
+    extern type go_##name;
+
+/*----------------------------------------------------------------------------*/
+
+extern void* hw;
+DECLARE_EXTERNS(cl_enginefunc_t, engine);
+DECLARE_EXTERNS(cl_clientfunc_t, client);
+
+/*----------------------------------------------------------------------------*/
+
+bool globals_init(void);
+
+#endif /* _GLOBALS_H */