Prereq: "3.5.0"
diff -ur --new-file /var/tmp/postfix-3.5.0/src/global/mail_version.h ./src/global/mail_version.h
--- /var/tmp/postfix-3.5.0/src/global/mail_version.h	2020-03-15 19:17:50.000000000 -0400
+++ ./src/global/mail_version.h	2020-04-18 10:45:42.000000000 -0400
@@ -20,8 +20,8 @@
   * Patches change both the patchlevel and the release date. Snapshots have no
   * patchlevel; they change the release date only.
   */
-#define MAIL_RELEASE_DATE	"20200316"
-#define MAIL_VERSION_NUMBER	"3.5.0"
+#define MAIL_RELEASE_DATE	"20200418"
+#define MAIL_VERSION_NUMBER	"3.5.1"
 
 #ifdef SNAPSHOT
 #define MAIL_VERSION_DATE	"-" MAIL_RELEASE_DATE
diff -ur --new-file /var/tmp/postfix-3.5.0/HISTORY ./HISTORY
--- /var/tmp/postfix-3.5.0/HISTORY	2020-03-15 19:15:53.000000000 -0400
+++ ./HISTORY	2020-04-18 11:18:40.000000000 -0400
@@ -24663,7 +24663,7 @@
 
 	Usability: the Postfix SMTP server now logs a warning when
 	a configuration requests access control by client certificate,
-	but "smtpd_tls_ask_clientcert = no".  Files: proto/postconf.proto,
+	but "smtpd_tls_ask_ccert = no". Files: proto/postconf.proto,
 	smtpd/smtpd_check.c.
 
 20200316
@@ -24671,3 +24671,12 @@
 	Removed the issuer_cn and subject_cn matches from
 	check_ccert_access. Files: smtpd/smtpd_check.c,
 	proto/postconf.proto.
+
+20200416
+
+	Workaround for broken builds after an incompatible change
+	in GCC 10. Files: makedefs, Makefile.in.
+
+	Workaround for broken DANE support after an incompatible
+	change in GLIBC 2.31. This avoids the need for new options
+	in /etc/resolv.conf. Files: dns/dns.h, dns/dns_lookup.c.
diff -ur --new-file /var/tmp/postfix-3.5.0/Makefile.in ./Makefile.in
--- /var/tmp/postfix-3.5.0/Makefile.in	2020-03-08 12:44:03.000000000 -0400
+++ ./Makefile.in	2020-04-16 13:07:58.000000000 -0400
@@ -1,7 +1,7 @@
 # To test with valgrind:
 # make -i tests VALGRIND="valgrind --tool=memcheck --log-file=/some/where.%p" 
 SHELL	= /bin/sh
-WARN    = -Wmissing-prototypes -Wformat -Wno-comment
+WARN    = -Wmissing-prototypes -Wformat -Wno-comment -fcommon
 OPTS	= 'WARN=$(WARN)'
 DIRS	= src/util src/global src/dns src/tls src/xsasl src/master src/milter \
 	src/postfix src/fsstone src/smtpstone \
diff -ur --new-file /var/tmp/postfix-3.5.0/makedefs ./makedefs
--- /var/tmp/postfix-3.5.0/makedefs	2020-03-07 20:22:38.000000000 -0500
+++ ./makedefs	2020-04-16 13:07:58.000000000 -0400
@@ -1136,7 +1136,7 @@
 : ${CC=gcc} ${OPT='-O'} ${DEBUG='-g'} ${AWK=awk} \
 ${WARN='-Wall -Wno-comment -Wformat -Wimplicit -Wmissing-prototypes \
 	-Wparentheses -Wstrict-prototypes -Wswitch -Wuninitialized \
-	-Wunused -Wno-missing-braces'}
+	-Wunused -Wno-missing-braces -fcommon'}
 
 # Extract map type names from -DHAS_XXX compiler options.  We avoid
 # problems with tr(1) range syntax by using enumerations instead,
diff -ur --new-file /var/tmp/postfix-3.5.0/src/dns/dns.h ./src/dns/dns.h
--- /var/tmp/postfix-3.5.0/src/dns/dns.h	2017-12-27 17:29:44.000000000 -0500
+++ ./src/dns/dns.h	2020-04-16 13:07:58.000000000 -0400
@@ -59,6 +59,7 @@
  */
 #ifdef NO_DNSSEC
 #undef RES_USE_DNSSEC
+#undef RES_TRUSTAD
 #endif
 
  /*
@@ -70,6 +71,9 @@
 #ifndef RES_USE_EDNS0
 #define RES_USE_EDNS0	0
 #endif
+#ifndef RES_TRUSTAD
+#define RES_TRUSTAD	0
+#endif
 
  /*-
   * TLSA: https://tools.ietf.org/html/rfc6698#section-7.1
diff -ur --new-file /var/tmp/postfix-3.5.0/src/dns/dns_lookup.c ./src/dns/dns_lookup.c
--- /var/tmp/postfix-3.5.0/src/dns/dns_lookup.c	2019-12-15 11:19:34.000000000 -0500
+++ ./src/dns/dns_lookup.c	2020-04-16 13:07:58.000000000 -0400
@@ -116,6 +116,9 @@
 /*	Request DNSSEC validation. This flag is silently ignored
 /*	when the system stub resolver API, resolver(3), does not
 /*	implement DNSSEC.
+/*	Automatically turns on the RES_TRUSTAD flag on systems that
+/*	support this flag (this behavior will be more configurable
+/*	in a later release).
 /* .RE
 /* .IP lflags
 /*	Flags that control the operation of the dns_lookup*()
@@ -458,10 +461,10 @@
     /*
      * Set extra options that aren't exposed to the application.
      */
-#define XTRA_FLAGS (RES_USE_EDNS0)
+#define XTRA_FLAGS (RES_USE_EDNS0 | RES_TRUSTAD)
 
     if (flags & RES_USE_DNSSEC)
-	flags |= RES_USE_EDNS0;
+	flags |= (RES_USE_EDNS0 | RES_TRUSTAD);
 
     /*
      * Can't append domains: we need the right SOA TTL.