--- firefox-49.0.2.orig/media/libyuv/source/scale_mips.cc	2016-05-12 19:13:17.000000000 +0200
+++ firefox-49.0.2/media/libyuv/source/scale_mips.cc	2016-11-11 18:23:07.984306408 +0100
@@ -18,7 +18,8 @@ extern "C" {
 
 // This module is for GCC MIPS DSPR2
 #if !defined(LIBYUV_DISABLE_MIPS) && \
-    defined(__mips_dsp) && (__mips_dsp_rev >= 2)
+    defined(__mips_dsp) && (__mips_dsp_rev >= 2) && \
+    (_MIPS_SIM == _MIPS_SIM_ABI32)
 
 void ScaleRowDown2_MIPS_DSPR2(const uint8* src_ptr, ptrdiff_t src_stride,
                               uint8* dst, int dst_width) {