Add an #include to appease an older clang, NFC

Add in a missing #include that AppleClang-900 complains about when
building with -DLLVM_ENABLE_MODULES.

llvm-svn: 320522

lldb/source/Utility/SelectHelper.cpp

@@ -32,6 +32,7 @@
 #define NOMINMAX
 #include <winsock2.h>
 #else
+#include <sys/time.h>
 #include <sys/select.h>
 #endif