Restart CI for New Technology and UBSAN hunting

Continuous Integration (via runit and runitd) is now re-enabled on win7
and win10. The `make test` command, which runs the tests on all systems
is now the fastest and most stable it's been since the project started.

UBSAN is now enabled in MODE=dbg in addition to ASAN. Many instances of
undefined behavior have been removed. Mostly things like passing a NULL
argument to memcpy(), which works fine with Cosmopolitan Libc, but that
doesn't prevents the compiler from being unhappy. There was an issue w/
GNU make where static analysis claims a sprintf() call can overflow. We
also now have nicer looking crash reports on Windows since uname should
now be supported and msys64 addr2line works reliably.

build/config.mk

@@ -131,7 +131,8 @@ CONFIG_CCFLAGS +=		\
 	-O2			\
 	-fno-inline
 CONFIG_COPTS +=			\
-	-fsanitize=address
+	-fsanitize=address	\
+	-fsanitize=undefined
 TARGET_ARCH ?=			\
 	-msse3
 OVERRIDE_CCFLAGS +=		\