git-svn-id: https://geuz.org/svn/gmsh/trunk@17063 59c8cabf-10d6-4a28-b43f-3936b85956c4
add some "const"

git-svn-id: https://geuz.org/svn/gmsh/trunk@17064 59c8cabf-10d6-4a28-b43f-3936b85956c4


git-svn-id: https://geuz.org/svn/gmsh/trunk@17065 59c8cabf-10d6-4a28-b43f-3936b85956c4