Attempt a very ugly workaround for mono/mono#16821.

Make.config

@@ -11,8 +11,7 @@ $(TOP)/Make.config.inc: $(TOP)/Make.config
 	@if test -d $(TOP)/../maccore; then printf "ENABLE_XAMARIN=1\n" >> $@; echo "Detected the maccore repository, automatically enabled the Xamarin build"; fi
 	@# Build from source for Xcode 11 support until mono has packages
 	@# TODO: to be removed when we can use the mono archive again.
-	#@printf "MONO_BUILD_FROM_SOURCE=1\n" >> $@; echo "Disabled the packaged mono build, since it's currently not supported in the xcode11 support branch."
-	#@ REVIEW: mono doesn't build from source in the 2019-06 branch (when we do it), so temporarly use packages again.
+	@printf "MONO_BUILD_FROM_SOURCE=1\n" >> $@; echo "Disabled the packaged mono build, since it's currently not supported in the xcode11 support branch."
 
 include $(TOP)/Make.versions
 

jenkins/build.sh

@@ -128,6 +128,16 @@ echo "Configuring the build with: $CONFIGURE_FLAGS"
 # shellcheck disable=SC2086
 ./configure $CONFIGURE_FLAGS
 
+COUNTER=0
+while [[ $COUNTER -lt 10 ]]; do
+	if make -j8; then
+		echo "Successful build after $COUNTER attempts."
+		break
+	else
+		echo "Build attempt #$COUNTER failed."
+		((COUNTER++))
+	fi
+done
 time make -j8
 time make install -j8