libarchive: Avoid a build error with OpenSSL 3.0.8

This disables warning-errors for:

    archive_hmac.c:241:64: error: passing argument 2 of
    'OSSL_PARAM_construct_utf8_string' discards 'const' qualifier from
    pointer target type [-Werror=discarded-qualifiers]

lib/libarchive/Makefile.inc

@@ -12,6 +12,10 @@ CFLAGS+=	-DPLATFORM_CONFIG_H=\"${.CURDIR}/config_freebsd.h\"
 CFLAGS+=	-DWITH_OPENSSL
 CFLAGS+=	-DOPENSSL_API_COMPAT=0x10100000L
 LIBADD+=	crypto
+#XXX for OpenSSL 3 with GCC12
+.if ${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} >= 120100
+CFLAGS.archive_hmac.c+=	-Wno-error=discarded-qualifiers
+.endif
 .else
 LIBADD+=	md
 .endif