--- a/media/libvpx/Makefile.in
+++ b/media/libvpx/Makefile.in
@@ -1,22 +1,25 @@
 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 # Set up the libvpx assembler config.
 
+include $(topsrcdir)/config/rules.mk
+
 ifdef VPX_ARM_ASM
 
 ifdef VPX_AS_CONVERSION
 # The ARM asm is written in ARM RVCT syntax, but we actually build it with
 # gas using GNU syntax. Add some rules to perform the conversion.
 
 # Previously used $(dir $(ASFILES)) to figure out which directories to generate.
 # However, .S (as opposed to .s) files are not added to ASFILES. There is only
 # one directory with arm assembly currently so enumerate it manually.
 GENERATED_DIRS += libvpx/vpx_dsp/arm
 
-%.asm.S: %.asm $(ASM_OFFSETS)
+%.asm.S: %.asm $(ASM_OFFSETS) $(call mkdir_deps,libvpx/vpx_dsp/arm)
 	$(VPX_AS_CONVERSION) < $< > $@
 
+$(addsuffix .$(OBJ_SUFFIX), idct4x4_add_neon.asm idct8x8_add_neon.asm idct16x16_add_neon.asm): libvpx/vpx_dsp/arm/idct_neon.asm.S
 endif
 endif