Upgrade to db/occt680beta commit 4e669d7
Upgrade patches to OCCT 6.8.0

Upgrade patches:
 MMGT-default-values.patch
 Print-null-handle.patch
 cmake/move-scripts-in-subdir.patch
 cmake/remove-Autotools-and-project-files.patch
 cppcheck/fix-return-reference-auto.patch
 modify-type-Standard_Boolean.patch
 ports/borland10.patch
 ports/borland11.patch
 ports/hpux.patch
 ports/mingw64-intptr_t-fixes.patch
 ports/rename-ED-variables-into-EData.patch
 ports/rename-glext.h.patch
 remove-duplicate-headers.patch
 submitted/thread_20051/fix-build-failure-powerpc.patch
 submitted/thread_20105/add-openmp-support.patch
 undef-Convex.patch
 unsorted.patch
 warning/fix-empty-conditional-body.patch
 warning/remove-const-return-value.patch
 warning/review-fix-unused-local-var.patch