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

[Hans Wennborg]

================
Comment at: tools/driver/driver.cpp:251
@@ +250,3 @@
+    while (!ProgNameRef.empty() &&
+           (isDigit(ProgNameRef.back()) || ProgNameRef.back() == '.'))
+      ProgNameRef = ProgNameRef.drop_back(1);
----------------
dblaikie wrote:
> the extra parens around the isDigit call are a bit confusing/misleading (I saw the end ')' and thought it was maybe grouped with the empty() call above for some reason)
The extra parenthesis are around the || expression.

Anyway, I've rewritten this with less parenthesis, and fitting on one line.

================
Comment at: tools/driver/driver.cpp:254
@@ +253,3 @@
+  }
+  SuffixIndex = FindDriverSuffix(ProgNameRef);
+
----------------
dblaikie wrote:
> Should this line be inside the prior if (but after/outside the loop)?
D'oh, yes it should. Done.

http://reviews.llvm.org/D5833