Subzero. Misc X86 fixes.

Makefile.standalone

 # The following variables will likely need to be modified, depending on where
 # and how you built LLVM & Clang. They can be overridden in a command-line
 # invocation of make, like:
 #
 #   make LLVM_SRC_PATH=<path> LIBCXX_INSTALL_PATH=<path> CLANG_PATH=<path> \
 #        PNACL_BIN_PATH=<path> ...
 #
 
 # LLVM_SRC_PATH is the path to the root of the checked out source code. This
 # directory should contain the configure script, the include/ and lib/
@@ skipping 194 matching lines @@
   SRCS += IceConverter.cpp \
         IceTypeConverter.cpp
 endif
 
 OBJS=$(patsubst %.cpp, $(OBJDIR)/%.o, $(SRCS))
 SB_OBJS=$(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 \
         AssemblerX8632/XmmArith.cpp \
         AssemblerX8632/ControlFlow.cpp \
         AssemblerX8632/Other.cpp \
         AssemblerX8632/X87.cpp \
         AssemblerX8664/LowLevel.cpp \
         AssemblerX8664/DataMov.cpp \
         AssemblerX8664/Locked.cpp \
         AssemblerX8664/GPRArith.cpp \
         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))
 
 # Keep all the first target so it's the default.
 all: $(OBJDIR)/pnacl-sz make_symlink runtime
 
 ifdef TSAN
 sb:
         @echo "Skipping pnacl-sz.*.nexe: TSAN isn't supported under NaCl."
@@ skipping 130 matching lines @@
 
 docs:
         doxygen Doxyfile
         @echo See file://`pwd`/docs/html/index.html
 
 clean:
         rm -rf pnacl-sz *.o $(OBJDIR) $(SB_OBJDIR) build/pnacl-sz.bloat.json
 
 clean-all: clean
         rm -rf build/ docs/