urdf: fix potential issues on Windows

9 jobs for pr/1342 in 170 minutes and 9 seconds (queued for 1 second)
Name Stage Failure
failed
format Test
-  
- casadi::SX max_x_y = pinocchio::math::max(x,y);
- casadi::SX max_x_0 = pinocchio::math::max(x,0.);
- casadi::SX max_0_y = pinocchio::math::max(0.,y);
-}

+ casadi:
Running after_script
Uploading artifacts for failed job
ERROR: Job failed: exit code 1
failed
robotpkg-py-pinocchio-py3-16.04-release Test
/root/robotpkg/math/pinocchio/work.runner-4rw8azke-project-5-concurrent-0/build.log
/root/robotpkg/mk/build/build.mk:198: recipe for target 'do-build' failed
make[1]: *** [do-build] Error 2
/root/robotpkg/mk/depends/depends.mk:70: recipe for target 'do-depends' failed
make: *** [do-depends] Error 1
make: *** [install] Error 2
/root/robotpkg/mk/internal/trusted.mk:36: recipe for target 'install' failed
Cleaning up file based variables
ERROR: Job failed: exit code 1