Don't include config.h in public headers

Replace it with llvm-config.h, which defines a subset of
config.h's macros "so that they can be in exported headers 
and won't override package specific directives", e.g.,
PACKAGE_NAME.

Endian.h wasn't using any macros at all though, so just delete
the include there instead.

llvm-svn: 133712

llvm/include/llvm/Support/Endian.h

@@ -14,7 +14,6 @@
 #ifndef LLVM_SUPPORT_ENDIAN_H
 #define LLVM_SUPPORT_ENDIAN_H
 
-#include "llvm/Config/config.h"
 #include "llvm/Support/Host.h"
 #include "llvm/Support/SwapByteOrder.h"
 #include "llvm/Support/type_traits.h"

llvm/include/llvm/Support/system_error.h

@@ -222,7 +222,7 @@ template <> struct hash<std::error_code>;
 
 */
 
-#include "llvm/Config/config.h"
+#include "llvm/Config/llvm-config.h"
 #include "llvm/Support/type_traits.h"
 #include <cerrno>
 #include <string>