gallivm: Use the LLVM's C disassembly interface.

It doesn't do everything we want.  In particular it doesn't allow to
detect jumps or return opcodes.  Currently we detect the x86's RET
opcode.

Even though it's worse for LLVM 3.3, it's an improvement for LLVM 3.7,
which was totally busted.

Reviewed-by: Roland Scheidegger <sroland@vmware.com>

scons/llvm.py

@@ -120,6 +120,7 @@ def generate(env):
             ])
         elif llvm_version >= distutils.version.LooseVersion('3.5'):
             env.Prepend(LIBS = [
+                'LLVMMCDisassembler',
                 'LLVMBitWriter', 'LLVMMCJIT', 'LLVMRuntimeDyld',
                 'LLVMX86Disassembler', 'LLVMX86AsmParser', 'LLVMX86CodeGen',
                 'LLVMSelectionDAG', 'LLVMAsmPrinter', 'LLVMX86Desc',
@@ -132,6 +133,7 @@ def generate(env):
             ])
         else:
             env.Prepend(LIBS = [
+                'LLVMMCDisassembler',
                 'LLVMBitWriter', 'LLVMX86Disassembler', 'LLVMX86AsmParser',
                 'LLVMX86CodeGen', 'LLVMX86Desc', 'LLVMSelectionDAG',
                 'LLVMAsmPrinter', 'LLVMMCParser', 'LLVMX86AsmPrinter',
@@ -189,7 +191,7 @@ def generate(env):
             if '-fno-rtti' in cxxflags:
                 env.Append(CXXFLAGS = ['-fno-rtti'])
 
-            components = ['engine', 'mcjit', 'bitwriter', 'x86asmprinter']
+            components = ['engine', 'mcjit', 'bitwriter', 'x86asmprinter', 'mcdisassembler']
 
             env.ParseConfig('llvm-config --libs ' + ' '.join(components))
             env.ParseConfig('llvm-config --ldflags')