diff --git js/src/Makefile.in js/src/Makefile.in
index 8eb385f..01bd8e3 100644
--- mozilla/js/src/Makefile.in
+++ mozilla/js/src/Makefile.in
@@ -323,6 +323,7 @@ endif
 
 ifneq (,$(filter arm% sparc %86 x86_64 mips%,$(TARGET_CPU)))
 ENABLE_YARR_JIT = 1
+DEFINES += -DENABLE_YARR_JIT=1
 
 VPATH += 	$(srcdir)/assembler/assembler \
 		$(srcdir)/methodjit \
diff --git js/src/assembler/wtf/Platform.h js/src/assembler/wtf/Platform.h
index 6570f2d..0c84896 100644
--- mozilla/js/src/assembler/wtf/Platform.h
+++ mozilla/js/src/assembler/wtf/Platform.h
@@ -1102,9 +1102,7 @@
 #if WTF_PLATFORM_CHROMIUM
 #define ENABLE_YARR_JIT 0
 
-#elif ENABLE_JIT && !defined(ENABLE_YARR_JIT)
-#define ENABLE_YARR_JIT 1
-
+#elif ENABLE_YARR_JIT
 /* Setting this flag compares JIT results with interpreter results. */
 #define ENABLE_YARR_JIT_DEBUG 0
 #endif
diff --git js/src/configure.in js/src/configure.in
index c142eb7..34f98b9 100644
--- mozilla/js/src/configure.in
+++ mozilla/js/src/configure.in
@@ -3347,7 +3347,10 @@ MOZ_ARG_ENABLE_STRING(debug,
                            (using compiler flags DBG)],
 [ if test "$enableval" != "no"; then
     MOZ_DEBUG=1
-    ENABLE_METHODJIT_SPEW=1
+    if test "$ENABLE_METHODJIT"; then
+         # needs MethodJIT or YarrJIT
+         ENABLE_METHODJIT_SPEW=1
+    fi
     if test -n "$enableval" -a "$enableval" != "yes"; then
         MOZ_DEBUG_FLAGS=`echo $enableval | sed -e 's|\\\ | |g'`
         _MOZ_DEBUG_FLAGS_SET=1