Expose CRC-32 implementation from zlib

llvm-svn: 188380
diff --git a/llvm/unittests/Support/CompressionTest.cpp b/llvm/unittests/Support/CompressionTest.cpp
index c8e2cd9..c0a9ada 100644
--- a/llvm/unittests/Support/CompressionTest.cpp
+++ b/llvm/unittests/Support/CompressionTest.cpp
@@ -63,6 +63,12 @@
   TestZlibCompression(BinaryDataStr, zlib::DefaultCompression);
 }
 
+TEST(CompressionTest, ZlibCRC32) {
+  EXPECT_EQ(
+      0x414FA339U,
+      zlib::crc32(StringRef("The quick brown fox jumps over the lazy dog")));
+}
+
 #endif
 
 }