Log Message:
libsecret: Directly patch Makefile.in to avoid automake

Previously if `automake' was not available during the build,
patch-libsecret_Makefile.am was effectively not applied to the Makefile.
To avoid to depends on `automake' just directly patch the Makefile.in.

Should fix the problem reported by Mayuresh on pkgsrc-users@
regarding the use of dollar single quotes ($'...') (also if `automake' is not
available!).