Switch LLVM_USE_RVALUE_REFERENCES to LLVM_HAS_RVALUE_REFERENCES.

Rationale:
1) This was the name in the comment block. ;]
2) It matches Clang's __has_feature naming convention.
3) It matches other compiler-feature-test conventions.

Sorry for the noise. =]

I've also switch the comment block to use a \brief tag and not duplicate
the name.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168996 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/unittests/ADT/TinyPtrVectorTest.cpp b/unittests/ADT/TinyPtrVectorTest.cpp
index 05dd797..15d5532 100644
--- a/unittests/ADT/TinyPtrVectorTest.cpp
+++ b/unittests/ADT/TinyPtrVectorTest.cpp
@@ -157,7 +157,7 @@
   this->expectValues(Copy2, this->testArray(42));
   this->expectValues(this->V2, this->testArray(0));
 
-#if LLVM_USE_RVALUE_REFERENCES
+#if LLVM_HAS_RVALUE_REFERENCES
   TypeParam Move(std::move(Copy2));
   this->expectValues(Move, this->testArray(42));
   this->expectValues(Copy2, this->testArray(0));
@@ -168,7 +168,7 @@
   this->V = this->V2;
   this->expectValues(this->V, this->testArray(0));
   this->expectValues(this->V2, this->testArray(0));
-#if LLVM_USE_RVALUE_REFERENCES
+#if LLVM_HAS_RVALUE_REFERENCES
   this->V = std::move(this->V2);
   this->expectValues(this->V, this->testArray(0));
 #endif
@@ -177,7 +177,7 @@
   this->V = this->V2;
   this->expectValues(this->V, this->testArray(0));
   this->expectValues(this->V2, this->testArray(0));
-#if LLVM_USE_RVALUE_REFERENCES
+#if LLVM_HAS_RVALUE_REFERENCES
   this->setVectors(this->testArray(1), this->testArray(0));
   this->V = std::move(this->V2);
   this->expectValues(this->V, this->testArray(0));
@@ -187,7 +187,7 @@
   this->V = this->V2;
   this->expectValues(this->V, this->testArray(0));
   this->expectValues(this->V2, this->testArray(0));
-#if LLVM_USE_RVALUE_REFERENCES
+#if LLVM_HAS_RVALUE_REFERENCES
   this->setVectors(this->testArray(2), this->testArray(0));
   this->V = std::move(this->V2);
   this->expectValues(this->V, this->testArray(0));
@@ -197,7 +197,7 @@
   this->V = this->V2;
   this->expectValues(this->V, this->testArray(0));
   this->expectValues(this->V2, this->testArray(0));
-#if LLVM_USE_RVALUE_REFERENCES
+#if LLVM_HAS_RVALUE_REFERENCES
   this->setVectors(this->testArray(42), this->testArray(0));
   this->V = std::move(this->V2);
   this->expectValues(this->V, this->testArray(0));
@@ -207,7 +207,7 @@
   this->V = this->V2;
   this->expectValues(this->V, this->testArray(1));
   this->expectValues(this->V2, this->testArray(1));
-#if LLVM_USE_RVALUE_REFERENCES
+#if LLVM_HAS_RVALUE_REFERENCES
   this->setVectors(this->testArray(0), this->testArray(1));
   this->V = std::move(this->V2);
   this->expectValues(this->V, this->testArray(1));
@@ -217,7 +217,7 @@
   this->V = this->V2;
   this->expectValues(this->V, this->testArray(2));
   this->expectValues(this->V2, this->testArray(2));
-#if LLVM_USE_RVALUE_REFERENCES
+#if LLVM_HAS_RVALUE_REFERENCES
   this->setVectors(this->testArray(0), this->testArray(2));
   this->V = std::move(this->V2);
   this->expectValues(this->V, this->testArray(2));
@@ -227,7 +227,7 @@
   this->V = this->V2;
   this->expectValues(this->V, this->testArray(42));
   this->expectValues(this->V2, this->testArray(42));
-#if LLVM_USE_RVALUE_REFERENCES
+#if LLVM_HAS_RVALUE_REFERENCES
   this->setVectors(this->testArray(0), this->testArray(42));
   this->V = std::move(this->V2);
   this->expectValues(this->V, this->testArray(42));
@@ -237,7 +237,7 @@
   this->V = this->V2;
   this->expectValues(this->V, this->testArray(1));
   this->expectValues(this->V2, this->testArray(1));
-#if LLVM_USE_RVALUE_REFERENCES
+#if LLVM_HAS_RVALUE_REFERENCES
   this->V = std::move(this->V2);
   this->expectValues(this->V, this->testArray(1));
 #endif
@@ -246,7 +246,7 @@
   this->V = this->V2;
   this->expectValues(this->V, this->testArray(2));
   this->expectValues(this->V2, this->testArray(2));
-#if LLVM_USE_RVALUE_REFERENCES
+#if LLVM_HAS_RVALUE_REFERENCES
   this->setVectors(this->testArray(1), this->testArray(2));
   this->V = std::move(this->V2);
   this->expectValues(this->V, this->testArray(2));
@@ -256,7 +256,7 @@
   this->V = this->V2;
   this->expectValues(this->V, this->testArray(42));
   this->expectValues(this->V2, this->testArray(42));
-#if LLVM_USE_RVALUE_REFERENCES
+#if LLVM_HAS_RVALUE_REFERENCES
   this->setVectors(this->testArray(1), this->testArray(42));
   this->V = std::move(this->V2);
   this->expectValues(this->V, this->testArray(42));
@@ -266,7 +266,7 @@
   this->V = this->V2;
   this->expectValues(this->V, this->testArray(1));
   this->expectValues(this->V2, this->testArray(1));
-#if LLVM_USE_RVALUE_REFERENCES
+#if LLVM_HAS_RVALUE_REFERENCES
   this->setVectors(this->testArray(2), this->testArray(1));
   this->V = std::move(this->V2);
   this->expectValues(this->V, this->testArray(1));
@@ -276,7 +276,7 @@
   this->V = this->V2;
   this->expectValues(this->V, this->testArray(2));
   this->expectValues(this->V2, this->testArray(2));
-#if LLVM_USE_RVALUE_REFERENCES
+#if LLVM_HAS_RVALUE_REFERENCES
   this->setVectors(this->testArray(2), this->testArray(2));
   this->V = std::move(this->V2);
   this->expectValues(this->V, this->testArray(2));
@@ -286,7 +286,7 @@
   this->V = this->V2;
   this->expectValues(this->V, this->testArray(42));
   this->expectValues(this->V2, this->testArray(42));
-#if LLVM_USE_RVALUE_REFERENCES
+#if LLVM_HAS_RVALUE_REFERENCES
   this->setVectors(this->testArray(2), this->testArray(42));
   this->V = std::move(this->V2);
   this->expectValues(this->V, this->testArray(42));
@@ -296,7 +296,7 @@
   this->V = this->V2;
   this->expectValues(this->V, this->testArray(1));
   this->expectValues(this->V2, this->testArray(1));
-#if LLVM_USE_RVALUE_REFERENCES
+#if LLVM_HAS_RVALUE_REFERENCES
   this->setVectors(this->testArray(42), this->testArray(1));
   this->V = std::move(this->V2);
   this->expectValues(this->V, this->testArray(1));
@@ -306,7 +306,7 @@
   this->V = this->V2;
   this->expectValues(this->V, this->testArray(2));
   this->expectValues(this->V2, this->testArray(2));
-#if LLVM_USE_RVALUE_REFERENCES
+#if LLVM_HAS_RVALUE_REFERENCES
   this->setVectors(this->testArray(42), this->testArray(2));
   this->V = std::move(this->V2);
   this->expectValues(this->V, this->testArray(2));
@@ -316,7 +316,7 @@
   this->V = this->V2;
   this->expectValues(this->V, this->testArray(42));
   this->expectValues(this->V2, this->testArray(42));
-#if LLVM_USE_RVALUE_REFERENCES
+#if LLVM_HAS_RVALUE_REFERENCES
   this->setVectors(this->testArray(42), this->testArray(42));
   this->V = std::move(this->V2);
   this->expectValues(this->V, this->testArray(42));
diff --git a/unittests/Support/Path.cpp b/unittests/Support/Path.cpp
index 63c9ae0..38bad8f 100644
--- a/unittests/Support/Path.cpp
+++ b/unittests/Support/Path.cpp
@@ -375,7 +375,7 @@
   
   // Unmap temp file
 
-#if LLVM_USE_RVALUE_REFERENCES
+#if LLVM_HAS_RVALUE_REFERENCES
   fs::mapped_file_region m(Twine(TempPath),
                              fs::mapped_file_region::readonly,
                              0,