- Convert include guards to #pragma once in salhelper, starmath, tools, ucb, and o3tl. - Kept changes minimal to a small cross-module batch as requested by the easyHack guidance. - Verified with: container=1 make -j4 o3tl.build salhelper.build starmath.build tools.build ucb.build Change-Id: Ic047061433985e12be41bdb6463ac4c8e8969ddd Reviewed-on: https://gerrit.libreoffice.org/c/core/+/204555 Reviewed-by: Julien Nabet <serval2412@yahoo.fr> Tested-by: Jenkins