php: update readme;

src/php/README.md

@@ -73,29 +73,24 @@ This will download and run the [gRPC install script][] and compile the gRPC PHP
 
 Clone this repository
 
-```
+```sh
 $ git clone https://github.com/grpc/grpc.git
 ```
 
-Build and install the Protocol Buffers compiler (protoc)
+Build and install the gRPC C core libraries
 
-```
+```sh
 $ cd grpc
 $ git pull --recurse-submodules && git submodule update --init --recursive
-$ cd third_party/protobuf
-$ ./autogen.sh
-$ ./configure
 $ make
-$ make check
 $ sudo make install
 ```
 
-Build and install the gRPC C core libraries
+Note: you may encounter a warning about the Protobuf compiler `protoc` 3.0.0+ not being installed. The following might help, and will be useful later on when we need to compile the `protoc-gen-php` tool.
 
 ```sh
-$ cd grpc
-$ make
-$ sudo make install
+$ cd grpc/third_party/protobuf
+$ sudo make install   # 'make' should have been run by core grpc
 ```
 
 Install the gRPC PHP extension