diff --git a/mp3lib/mpg123.h b/mp3lib/mpg123.h
index 3d98366b4f..5a7548250a 100644
--- a/mp3lib/mpg123.h
+++ b/mp3lib/mpg123.h
@@ -134,7 +134,7 @@ void dct64_MMX_3dnow(short *, short *, real *);
 void dct64_MMX_3dnowex(short *, short *, real *);
 void dct64_sse(short *, short *, real *);
 void dct64_altivec(real *, real *, real *);
-void (*dct64_MMX_func)(short *, short *, real *);
+extern void (*dct64_MMX_func)(short *, short *, real *);
 
 void mp3lib_dct64(real *, real *, real *);
 
diff --git a/mp3lib/sr1.c b/mp3lib/sr1.c
index 72502d61ee..694961ebc0 100644
--- a/mp3lib/sr1.c
+++ b/mp3lib/sr1.c
@@ -387,6 +387,8 @@ static int _has_mmx = 0;  // used by layer2.c, layer3.c to pre-scale coeffs
 /*           PUBLIC FUNCTIONS                  */
 /******************************************************************************/
 
+void (*dct64_MMX_func)(short *, short *, real *);
+
 #include "layer2.c"
 #include "layer3.c"
 #include "layer1.c"