docs/building.md: add note about forcing a static build of mraa
@@ -106,6 +106,9 @@ You can also enable -Wall for gcc before running cmake by exporting your wanted
CC flags to the CC env var
`export CC="gcc -Wall"`
+Sometimes it's nice to build a static libary, on Linux systems just set
+ `-DBUILD_SHARED_LIBS=OFF`
+
## Dependencies continued
You'll need at least SWIG version 3.0.2 and we recommend 3.0.5 to build the
