typo

Author: James Barnett

README.md

@@ -14,7 +14,7 @@ to `/usr/local/include`. To choose a specific directory for installation you can
 use `PREFIX`. For example, the following installs the library to
 `/home/wes/xdrfile`.
 
-    $ make PREFIX=/home/wes/xdrfile
+    $ make PREFIX=/home/wes/xdrfile install
 
 A pkg-config file is included for use in compiling other programs. You may need
 to set `PKG_CONFIG_PATH` to its location (by default `/usr/local/lib/pkgconfig`).