Added inclusion of dlfcn.h from old 5.1 tree

include/my_global.h

@@ -1361,4 +1361,23 @@ do { doubleget_union _tmp; \
 #define NO_EMBEDDED_ACCESS_CHECKS
 #endif
 
+#ifdef HAVE_DLOPEN
+#if defined(__WIN__)
+#define dlsym(lib, name) GetProcAddress((HMODULE)lib, name)
+#define dlopen(libname, unused) LoadLibraryEx(libname, NULL, 0)
+#define dlclose(lib) FreeLibrary((HMODULE)lib)
+#elif defined(HAVE_DLFCN_H)
+#include <dlfcn.h>
+#endif
+#endif
+
+/* FreeBSD 2.2.2 does not define RTLD_NOW) */
+#ifndef RTLD_NOW
+#define RTLD_NOW 1
+#endif
+
+#ifndef HAVE_DLERROR
+#define dlerror() ""
+#endif
+
 #endif /* my_global_h */