SW-610: Specify 'native' CPU optimisation instead of 'haswell'

Docker/lofar-base/Dockerfile.tmpl

@@ -63,7 +63,7 @@ ENV CASACORE_VERSION=v3.0.0 \
 #
 ARG J=6
 ENV J=${J} \
-    CXX_FLAGS="--std=c++11 -W -Wall -Woverloaded-virtual -Wno-unknown-pragmas -D_GLIBCXX_USE_CXX11_ABI=${CXX_ABI} -O3 -march=haswell"
+    CXX_FLAGS="--std=c++11 -W -Wall -Woverloaded-virtual -Wno-unknown-pragmas -D_GLIBCXX_USE_CXX11_ABI=${CXX_ABI} -O3 -march=native"
 
 #
 # Base and runtime dependencies