--- mozilla/old-configure.in.orig	2018-07-12 02:18:02.000000000 +0000
+++ mozilla/old-configure.in	2018-07-12 02:18:03.000000000 +0000
@@ -866,7 +866,7 @@
 *-darwin*)
     MKSHLIB='$(CXX) $(CXXFLAGS) $(DSO_PIC_CFLAGS) $(DSO_LDOPTS) -o $@'
     MKCSHLIB='$(CC) $(CFLAGS) $(DSO_PIC_CFLAGS) $(DSO_LDOPTS) -o $@'
-    MOZ_OPTIMIZE_FLAGS="-O3"
+    MOZ_OPTIMIZE_FLAGS="-O3 -fno-schedule-insns"
     CXXFLAGS="$CXXFLAGS -stdlib=libc++"
     DLL_SUFFIX=".dylib"
     DSO_LDOPTS=''