Subzero. Misc X86 fixes.

Makefile.standalone

Index: Makefile.standalone
diff --git a/Makefile.standalone b/Makefile.standalone
index 746d216208d0b2a44bd29ab67c931e4cf2ddba99..caf6b8ba0ec286bd6d0acfccf1cd9fd32a533144 100644
--- a/Makefile.standalone
+++ b/Makefile.standalone
@@ -212,8 +212,12 @@ SB_OBJS=$(patsubst %.cpp, $(SB_OBJDIR)/%.o, $(SRCS))
 UNITTEST_SRCS = \
 	BitcodeMunge.cpp \
 	IceELFSectionTest.cpp \
-	IceParseInstsTest.cpp \
-        AssemblerX8632/LowLevel.cpp \
+	IceParseInstsTest.cpp
+
+# The X86 assembler tests take too long to compile. Given how infrequently the
+# assembler will change, we disable them.
+ifdef CHECK_X86_ASM
+  UNITTEST_SRCS += AssemblerX8632/LowLevel.cpp \
         AssemblerX8632/DataMov.cpp \
         AssemblerX8632/Locked.cpp \
         AssemblerX8632/GPRArith.cpp \
@@ -228,7 +232,7 @@ UNITTEST_SRCS = \
         AssemblerX8664/XmmArith.cpp \
         AssemblerX8664/ControlFlow.cpp \
         AssemblerX8664/Other.cpp
-
+endif
 
 UNITTEST_OBJS = $(patsubst %.cpp, $(OBJDIR)/unittest/%.o, $(UNITTEST_SRCS))
 UNITTEST_LIB_OBJS = $(filter-out $(OBJDIR)/main.o,$(OBJS))