sysutils/vtm: update 0.9.99.70 -> 2025.05.21, fix build on i386 and armv6/7
NOTE: This vtm release is not compatible with previous versions
- for i386/arm6/7 o Use GCC for build because clang doesn't allow use of libstdc++. o Build fails on armv6/7 and i386 architectures with use of libc++. o Using libc++, both compilers runs out of memory, so, we need to explicitly use libstdc++ here.
PR: 285708
Reviewed-by: marklmi26-fbsd@yahoo.com
Changes: https://github.com/directvt/vtm/releases