- Fix build with SSL on 12.0

Vsftpd uses an ugly way of checking whether it needs to link
libssl/libcrypto by grepping object file (!) for SSL_library_init
(which may be or not be actually used depending on a define).
This does not work if SSL_library_init is a macro which is the case
with OpenSSL 1.1.0:

/usr/include/openssl/ssl.h:#  define SSL_library_init() OPENSSL_init_ssl(0, NULL)

Because of this, on 12.0 the check always fails, OpenSSL libs are
not linked, and the build fails with linker errors:

/usr/bin/ld: error: undefined symbol: OPENSSL_init_ssl
>>> referenced by ssl.c
>>>               ssl.o:(ssl_init)

/usr/bin/ld: error: undefined symbol: TLS_server_method
>>> referenced by ssl.c
>>>               ssl.o:(ssl_init)

/usr/bin/ld: error: undefined symbol: SSL_CTX_new
>>> referenced by ssl.c
>>>               ssl.o:(ssl_init)

Since we know beforehand whether we need SSL, just replace the check
with true if SSL is enabled.

- While here, partially convert to options helpers

ftp/vsftpd-ext/Makefile

@@ -53,6 +53,9 @@ CFLAGS+=	-I${OPENSSLINC}
 LDFLAGS+=	-L${OPENSSLLIB}
 .endif
 
+post-patch-VSFTPD_SSL-on:
+	@${REINPLACE_CMD} -e 's|find_func SSL_library_init ssl.o|true|' ${WRKSRC}/vsf_findlibs.sh
+
 do-configure:
 .if ${PORT_OPTIONS:MVSFTPD_SSL} && !defined(WITHOUT_SSL)
 	${REINPLACE_CMD} -e \
@@ -97,13 +100,13 @@ do-install:
 	${INSTALL_MAN} ${WRKSRC}/vsftpd.conf.5 ${STAGEDIR}${PREFIX}/man/man5/
 	${INSTALL_MAN} ${WRKSRC}/vsftpd.8 ${STAGEDIR}${PREFIX}/man/man8/
 	${MKDIR} ${STAGEDIR}/var/ftp ${STAGEDIR}${PREFIX}/share/vsftpd/empty
-.if ${PORT_OPTIONS:MDOCS}
+
+do-install-DOCS-on:
 	${MKDIR} ${STAGEDIR}${DOCSDIR}
 	${INSTALL_DATA} ${DOCFILES:S,^,${WRKSRC}/,} ${STAGEDIR}${DOCSDIR}/
 .for i in EXAMPLE SECURITY
 	${MKDIR} ${STAGEDIR}${DOCSDIR}/${i}
 	${CP} -p -R -L ${WRKSRC}/${i}/./ ${STAGEDIR}${DOCSDIR}/${i}/
 .endfor
-.endif
 
 .include <bsd.port.mk>