[Bug 43971] Wine 2.20 Bcrypt compilation fails under older linux systems while Wine 2.0.3 compiles fine

https://bugs.winehq.org/show_bug.cgi?id=43971

--- Comment #6 from Kol  ---
This is not a Wine bug nor a compiler bug, but is an incompatibility
between recent Wine versions and old version of GnuTLS. On my very
old system equipped with GnuTLS 2.4.2 in the file <gnutls/gnutls.h>
in the definition of type "gnutls_retr_st" there is a union member

union key
{ ...
} key;

which is in contradiction with "struct key" in "bcrypt_main.c".
In newer versions of GnuTLS this union type becomes nameless:

union
{ ...
} key;

So the solution is or to upgrade GnuTLS, or simply to replace
the string "union key" with "union" in the file
"/usr/include/gnutls/gnutls.h".