Restored GitHub compiling workflow to us // builds

Author: egallesio

.github/workflows/ccpp.yml

@@ -14,7 +14,7 @@ jobs:
     - name: configure
       run: ./configure
     - name: make
-      run: make -j1
+      run: make -j$(nproc)
     - name: make check
       run: make check
 #    - name: make distcheck