Glibc does not properly support static binaries, you need libc around even for static binaries mostly (eg dns resolution). Its annoying. You can make real static binaries with Musl libc though, or on the BSDs.
Well currently this applies to Go as well: when linking to the "net" package it links to the system libc shared library for the same reason.
You can build your binary with the netgo build tag, but you must take into consideration that your binary might not behave correctly when running on systems with customised name resolution (NSS) settings, such as nss-ldap etc.