Adds extern "C" ints to the .cpp files that use RegisterTarget, as
well as 2 files that use "Registrator"s. These are to be used by the
MSVC builds, as the Win32 linker does not include libs that are
otherwise unreferenced, even if global constructors in the lib have
side-effects.

Patch by Scott Graham!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@59378 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/CBackend/CBackend.cpp b/lib/Target/CBackend/CBackend.cpp
index 6e69b9e..e8804dc 100644
--- a/lib/Target/CBackend/CBackend.cpp
+++ b/lib/Target/CBackend/CBackend.cpp
@@ -48,6 +48,14 @@
 #include <sstream>
 using namespace llvm;
 
+/// CBackendTargetMachineModule - Note that this is used on hosts that
+/// cannot link in a library unless there are references into the
+/// library.  In particular, it seems that it is not possible to get
+/// things to work on Win32 without this.  Though it is unused, do not
+/// remove it.
+extern "C" int CBackendTargetMachineModule;
+int CBackendTargetMachineModule = 0;
+
 // Register the target.
 static RegisterTarget<CTargetMachine> X("c", "C backend");