Start adding an integrated assembler.

src/llvm2ice.cpp

Index: src/llvm2ice.cpp
diff --git a/src/llvm2ice.cpp b/src/llvm2ice.cpp
index e704ed3f33b11177d9fe408c5a6e4cd99f3dfbd1..e393cf3e4324320d7d34183f8e382426d5177bb4 100644
--- a/src/llvm2ice.cpp
+++ b/src/llvm2ice.cpp
@@ -108,6 +108,10 @@ static cl::opt<bool>
 BuildOnRead("build-on-read",
             cl::desc("Build ICE instructions when reading bitcode"),
             cl::init(false));
+static cl::opt<bool>
+    UseIntegratedAssembler("integrated-as",
+                           cl::desc("Use integrated assembler (default yes)"),
+                           cl::init(true));
 
 int main(int argc, char **argv) {
 
@@ -138,6 +142,7 @@ int main(int argc, char **argv) {
   Flags.DisableGlobals = DisableGlobals;
   Flags.FunctionSections = FunctionSections;
   Flags.UseSandboxing = UseSandboxing;
+  Flags.UseIntegratedAssembler = UseIntegratedAssembler;
 
   Ice::GlobalContext Ctx(Ls, Os, VMask, TargetArch, OptLevel, TestPrefix,
                          Flags);