Merge pull request #293 from supercollider/minor-build-instruction-im…

…provements

added a note about using sudo under linux

README.md

@@ -58,11 +58,12 @@ replace `/path/to/sc/` with the path to the SuperCollider source directory. That
 `../../supercollider` if you cloned both repositories in the same working directory.
 
 ```shell
+cd sc3-plugins
 mkdir build && cd build
 # for both scsynth and supernova plugins; omit -DSUPERNOVA=ON to build only scsynth plugins
 cmake -DSC_PATH=/path/to/sc/ -DCMAKE_BUILD_TYPE=Release -DSUPERNOVA=ON ..
 cmake --build . --config Release
-# to install the plugins
+# to install the plugins - note: linux users likely need sudo
 cmake --build . --config Release --target install
 ```