adding dlvsym support for linux/GNU, freebsd, dragonflybsd and netbsd. #4671
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ref: https://linux.die.net/man/3/dlvsym
ref: https://man.freebsd.org/cgi/man.cgi?query=dlvsym
ref: https://github.com/DragonFlyBSD/DragonFlyBSD/blob/088552723935447397400336f5ddb7aa5f5de660/include/dlfcn.h#L126
ref: https://man.netbsd.org/dlfcn.3