mail/anubis: the port had been improved (+)

- Unbreak the build against recent gdbm based on the patch provided by
  the upstream maintainer*; this breakage went unnoticed for a while
  because GDBM option was disabled by default -- enable it so we would
  notice similar breakages next time (most of other ports by the same
  upstream author/maintainer already default to it; this is very light
  dependency yet useful enough as default database backend)

- Drop MAKE_JOBS_UNSAFE which had been added back in r269161 ten years
  ago for version 4.1.1 and never properly explained; even though the
  ChangeLog does not explicitly mention parallel build-related fixes,
  the author confirmed that he does not recall any problems regarding
  parallel builds; assume that it either was fixed in the meantime, or
  would manifest itself again, only this time we'd catch the bug and,
  at the very least, would properly document it (but ideally fix)

*) https://mail.gnu.org/archive/html/bug-anubis/2020-06/msg00004.html

mail/anubis/Makefile

@@ -23,13 +23,12 @@ GNU_CONFIGURE=	yes
 INFO=		anubis
 PORTEXAMPLES=	1anubisrc 2anubisrc
 
-MAKE_JOBS_UNSAFE=	yes
-
 OPTIONS_DEFINE=		NLS EXAMPLES EMACS GUILE GNUPG GNUTLS \
 			GSASL LIBWRAP PCRE PAM SOCKS TEST
+DB_DESC=		Database backend
 OPTIONS_GROUP=		DB
 OPTIONS_GROUP_DB=	GDBM MYSQL PGSQL
-OPTIONS_DEFAULT=	GUILE GNUPG GNUTLS GSASL
+OPTIONS_DEFAULT=	GDBM GNUPG GNUTLS GSASL GUILE
 OPTIONS_EXCLUDE_aarch64=TEST
 OPTIONS_SUB=		yes
 NO_OPTIONS_SORT=	yes
@@ -46,7 +45,6 @@ EMACS_USES=		emacs:build
 EMACS_CONFIGURE_ON=	--with-lispdir=${PREFIX}/${EMACS_SITE_LISPDIR}/anubis
 EMACS_CONFIGURE_OFF=	--with-lispdir=no
 
-GDBM_DESC=		GDBM backend
 GDBM_IMPLIES=		GSASL
 GDBM_LIB_DEPENDS=	libgdbm.so:databases/gdbm
 GDBM_CONFIGURE_WITH=	gdbm
@@ -100,6 +98,9 @@ SUB_LIST+=	REQUIRE="${REQUIRE}"
 
 post-patch:
 	@${REINPLACE_CMD} -e "s|/etc|${PREFIX}/etc|g" ${WRKSRC}/src/headers.h
+	@${REINPLACE_CMD} -e 's,gdbm_db_,db_gdbm_,g' \
+		${WRKSRC}/src/anubisadm.c ${WRKSRC}/src/gdbm.c \
+		${WRKSRC}/src/headers.h ${WRKSRC}/src/main.c
 
 post-patch-TEST-off:
 	@${REINPLACE_CMD} -e 's| testsuite||' ${WRKSRC}/Makefile.am