COMMON: fix iOS compile error

Author: chrisws

src/common/extlib.c

@@ -22,7 +22,7 @@
  #define WIN_EXTLIB
  #define LIB_EXT ".dll"
  #define DEFAULT_PATH "c:/sbasic/lib"
-#elif defined(__linux__) || defined(__midipix__) && defined(_UnixOS)
+#elif (defined(__linux__) || defined(__midipix__) || defined(__MACH__)) && defined(_UnixOS)
  #include <dlfcn.h>
  #define LNX_EXTLIB
  #define LIB_EXT ".so"