Use a better default value for parallel jobs.

Author: jnealtowns

setup.env

@@ -23,7 +23,7 @@ export PATH="$ONL/tools/scripts:$ONL/tools:$PATH"
 
 # Parallel Make Jobs
 # Default parallel build settings
-export ONL_MAKE_PARALLEL=-j16
+export ONL_MAKE_PARALLEL=-j$(echo "$(nproc) * 2" | bc)
 
 # Version files
 $ONL/tools/make-versions.py --import-file=$ONL/tools/onlvi --class-name=OnlVersionImplementation --output-dir $ONL/make/versions