Change compilation options for continuous integration

The new machine is better. It is now possible to compile the code
using the '-j 4' flag

.gitlab-ci/clang10-mpi-debug.yml

@@ -6,7 +6,7 @@ test:clang10-mpi-debug:
     - mkdir -p build/clang10-debug-mpi
     - cd build/clang10-debug-mpi
     - CXX=clang++-10 CC=clang-10 cmake ../.. -DCMAKE_BUILD_TYPE=Debug
-    - make
+    - make -j 4
     - make check
   cache:
     key: "${CI_COMMIT_REF_SLUG}-clang10-debug-mpi"

.gitlab-ci/clang10-mpi-release.yml

@@ -6,7 +6,7 @@ test:clang10-mpi-release:
     - mkdir -p build/clang10-release-mpi
     - cd build/clang10-release-mpi
     - CXX=clang++-10 CC=clang-10 cmake ../.. -DCMAKE_BUILD_TYPE=Release -DCLANG_FORMAT=/usr/bin/clang-format-10
-    - make
+    - make -j 4
     - make check
   cache:
     key: "${CI_COMMIT_REF_SLUG}-clang10-release-mpi"

.gitlab-ci/gcc10-mpi-coverage.yml

@@ -6,7 +6,7 @@ coverage:gcc10-mpi-coverage:
     - mkdir -p build/gcc10-cov-mpi
     - cd build/gcc10-cov-mpi
     - CXX=g++-10 CC=gcc-10 cmake ../.. -DCMAKE_BUILD_TYPE=Coverage
-    - make
+    - make -j 4
   cache:
     key: "${CI_COMMIT_REF_SLUG}-gcc10-cov-mpi"
     paths:

.gitlab-ci/gcc10-mpi-release.yml

@@ -6,7 +6,7 @@ test:gcc10-mpi-release:
     - mkdir -p build/gcc10-release-mpi
     - cd build/gcc10-release-mpi
     - CXX=g++-10 CC=gcc-10 cmake ../.. -DCMAKE_BUILD_TYPE=Release
-    - make
+    - make -j 4
     - make test
   cache:
     key: "${CI_COMMIT_REF_SLUG}-gcc10-release-mpi"

.gitlab-ci/gcc10-seq-coverage.yml

@@ -6,7 +6,7 @@ coverage:gcc10-seq-coverage:
     - mkdir -p build/gcc10-cov
     - cd build/gcc10-cov
     - CXX=g++-10 CC=gcc-10 cmake ../.. -DCMAKE_BUILD_TYPE=Coverage
-    - make
+    - make -j 4
   cache:
     key: "${CI_COMMIT_REF_SLUG}-gcc10-cov"
     paths:

.gitlab-ci/gcc10-seq-release.yml

@@ -6,7 +6,7 @@ test:gcc10-seq-release:
     - mkdir -p build/gcc10-release-seq
     - cd build/gcc10-release-seq
     - CXX=g++-10 CC=gcc-10 cmake ../.. -DCMAKE_BUILD_TYPE=Release
-    - make
+    - make -j 4
     - make check
   cache:
     key: "${CI_COMMIT_REF_SLUG}-gcc10-release-seq"