[PATCH] Driver: support detecting driver mode when clang has a version suffix without dash (PR21094)

[David Blaikie]

================
Comment at: tools/driver/driver.cpp:258
@@ +257,3 @@
+  if (!DS) {
+    // Try again after stripping trailing -component.
+    ProgNameRef = ProgNameRef.slice(0, ProgNameRef.rfind('-'));
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Might help if these comments were maybe illustrated with an example:

  // Strip trailing version: clang-3.4 -> clang

  // Strip trailing -component: clang-foo -> clang

http://reviews.llvm.org/D5833