Update to opus-HEAD-66611f1.

celt/arm/fixed_armv4.h

 /* Copyright (C) 2013 Xiph.Org Foundation and contributors */
 /*
    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions
    are met:
 
    - Redistributions of source code must retain the above copyright
    notice, this list of conditions and the following disclaimer.
 
    - Redistributions in binary form must reproduce the above copyright
@@ skipping 50 matching lines @@
 }
 #define MULT16_32_Q15(a, b) (MULT16_32_Q15_armv4(a, b))
 
 
 /** 16x32 multiply, followed by a 15-bit shift right and 32-bit add.
     b must fit in 31 bits.
     Result fits in 32 bits. */
 #undef MAC16_32_Q15
 #define MAC16_32_Q15(c, a, b) ADD32(c, MULT16_32_Q15(a, b))
 
+/** 16x32 multiply, followed by a 16-bit shift right and 32-bit add.
+    Result fits in 32 bits. */
+#undef MAC16_32_Q16
+#define MAC16_32_Q16(c, a, b) ADD32(c, MULT16_32_Q16(a, b))
 
 /** 32x32 multiplication, followed by a 31-bit shift right. Results fits in 32 bits */
 #undef MULT32_32_Q31
 #define MULT32_32_Q31(a,b) (opus_val32)((((opus_int64)(a)) * ((opus_int64)(b)))>>31)
 
 #endif