faq2: update

content/pages/faq.md

@@ -180,7 +180,7 @@ guix shell --pure -D starpu -- /bin/bash --norc
 ./autogen.sh
 rm build -rf && mkdir build && cd build
 ../configure --prefix=$PWD/install --enable-debug --disable-opencl
-make -j install
+make -j20 install
 exit
 ```
 
@@ -192,7 +192,7 @@ cd chameleon
 guix shell --pure -D chameleon -- /bin/bash --norc
 export PKG_CONFIG_PATH=/tmp/starpu/build/install/lib/pkgconfig:$PKG_CONFIG_PATH
 cmake -B build -DCMAKE_BUILD_TYPE=Debug -DCHAMELEON_USE_MPI=ON
-cmake --build build -j
+cmake --build build -j20
 exit
 ```