In {rG962058f7}, the tilde expansion support is added for the argument handling.
This change breaks use of semi-hosted environment. Namely, using Wine emulation for testing Windows binaries on GNU/Linux host.
Specifically, in the tests by gpgscm, initial setup fails because `gpg-connect-agent` cannot spawn `gpg-agent` any more.
Apparently, replacing `/` by `\` changes the semantics (gpgrt_access function fails for `\home\gniibe\build\mingw-i686\gnupg\agent\gpg-agent.exe`).