swscale: revive SWS_CPU_CAPS until next major bump.

libswscale/swscale.h

@@ -50,6 +50,9 @@
 #ifndef FF_API_SWS_GETCONTEXT
 #define FF_API_SWS_GETCONTEXT  (LIBSWSCALE_VERSION_MAJOR < 2)
 #endif
+#ifndef FF_API_SWS_CPU_CAPS
+#define FF_API_SWS_CPU_CAPS    (LIBSWSCALE_VERSION_MAJOR < 2)
+#endif
 
 /**
  * Returns the LIBSWSCALE_VERSION_INT constant.
@@ -95,13 +98,18 @@ const char *swscale_license(void);
 #define SWS_ACCURATE_RND      0x40000
 #define SWS_BITEXACT          0x80000
 
-//The following flags are only provided for API/ABI compatibility they have no effect anymore
+#if FF_API_SWS_CPU_CAPS
+/**
+ * CPU caps are autodetected now, those flags
+ * are only provided for API compatibility.
+ */
 #define SWS_CPU_CAPS_MMX      0x80000000
 #define SWS_CPU_CAPS_MMX2     0x20000000
 #define SWS_CPU_CAPS_3DNOW    0x40000000
 #define SWS_CPU_CAPS_ALTIVEC  0x10000000
 #define SWS_CPU_CAPS_BFIN     0x01000000
 #define SWS_CPU_CAPS_SSE2     0x02000000
+#endif
 
 #define SWS_MAX_REDUCE_CUTOFF 0.002