Fix build instructions for MySQL vs MariaDB

README.md

@@ -6,26 +6,35 @@ C module for MySQL
 **To build on macOS:**
 
 ```sh
-swift build -Xlinker -L/usr/local/lib
+swift build -Xswiftc -I/usr/local/include/mysql -Xlinker -L/usr/local/lib
 ```
 
+- `-I` tells the compiler where to find the MySQL header file `mysql.h`.
+- `-L` tells the linker where to find MySQL library `libmysqlclient`.
+
 **To build on Linux:**
 
+`swift build` should work normally.
+
+## MariaDB
+
+To use MariaDB instead of MySQL, you just need to change a couple of the compiler flags.
+
+**macOS:**
+
 ```sh
-swift build -Xswiftc -I/usr/include/mariadb -Xlinker -L/usr/lib/x86_64-linux-gnu
+swift build -Xlinker -L/usr/local/lib -Xswiftc -DMARIADB -Xswiftc -DNOJSON
 ```
 
-- `-I` tells the compiler where to find the MariaDB header file `mysql.h`
-- `-L` tells the linker where to find MariaDB library.
-  - On macOS the library is called `libmysqlclient`, and on Linux the library is `libmariadb`.
-
-## MariaDB
+- `-DMARIADB` tells the compiler to link the MariaDB library instead of the MySQL library.
+- `-DNOJSON` tells the package to ignore the `JSON` type (not supported as of MariaDB 10.1.16).
 
-To use MariaDB instead of MySQL, add the following compiler flag when building:
+**Linux:**
 
 ```sh
--Xswiftc -DMARIADB
+swift build -Xswiftc -I/usr/include/mariadb -Xlinker -L/usr/lib/x86_64-linux-gnu -Xswiftc -DMARIADB -Xswiftc -DNOJSON
 ```
 
-- This tells the compiler to link the MariaDB library instead of the MySQL library.
+- This simply changes the library/header paths and sets the same compatibility options shown above.
+- Note that on macOS the library is called `libmysqlclient`, while on Linux the library is called `libmariadb`.