Updated README.md
Added relative link to cmake guide.
diff --git a/src/README.md b/src/README.md
index 4e312c0..c85bad3 100644
--- a/src/README.md
+++ b/src/README.md
@@ -181,7 +181,7 @@
It contains the protoc binary as well as public proto files of protobuf
library.
-To build from source using Microsoft Visual C++, see cmake/README.md.
+To build from source using Microsoft Visual C++, see [cmake/README.md](../cmake/README.md).
To build from source using Cygwin or MinGW, follow the Unix installation
instructions, above.