Merge with FreeBSD branch ino64.

Rename shlib-compat to shlib-compat.py.
Import makesyscalls-fake.sh.
Update README.
Skip tags dwarfdump can't parse.

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FreeeBSD-CURRENT switched to .debug suffix for shared libraries with debugging.
Replace LIBC_EXTRAMK hack documentation with generic solution.
Update makesyscalls-fake.sh to fix build errors on CURRENT.
Remove syscall stubs from libtestsys. Connect libtestsys to build.

Test should be used to verify makesyscalls-fake.sh result is buildable.