build: align minimum build dependencies with ndn-cxx

 * Recommend gcc >= 7.4.0
 * Require clang >= 4.0, or Xcode >= 9.0 on macOS
 * Silence an ABI-related diagnostic message from gcc on armv7
 * Update Travis CI job matrix

Refs: #5087, #5106
Change-Id: I71aef00147a7ad93b537904bb309745fed77f509
diff --git a/.jenkins.d/20-tests.sh b/.jenkins.d/20-tests.sh
index d4b9652..9ea3853 100755
--- a/.jenkins.d/20-tests.sh
+++ b/.jenkins.d/20-tests.sh
@@ -3,28 +3,8 @@
 
 # Prepare environment
 rm -rf ~/.ndn
-
-if has OSX $NODE_LABELS; then
-    security unlock-keychain -p named-data
-fi
-
 ndnsec-keygen "/tmp/jenkins/$NODE_NAME" | ndnsec-install-cert -
 
-BOOST_VERSION=$(python3 -c "import sys; sys.path.append('build/c4che'); import _cache; print(_cache.BOOST_VERSION_NUMBER);")
-
-ut_log_args() {
-    if (( BOOST_VERSION >= 106200 )); then
-        echo --logger=HRF,test_suite,stdout:XML,all,build/xunit-${1:-report}.xml
-    else
-        if [[ -n $XUNIT ]]; then
-            echo --log_level=all $( (( BOOST_VERSION >= 106000 )) && echo -- ) \
-                 --log_format2=XML --log_sink2=build/xunit-${1:-report}.xml
-        else
-            echo --log_level=test_suite
-        fi
-    fi
-}
-
 # https://github.com/google/sanitizers/wiki/AddressSanitizerFlags
 ASAN_OPTIONS="color=always"
 ASAN_OPTIONS+=":check_initialization_order=1"
@@ -37,6 +17,8 @@
 
 export BOOST_TEST_BUILD_INFO=1
 export BOOST_TEST_COLOR_OUTPUT=1
+export BOOST_TEST_DETECT_MEMORY_LEAK=0
+export BOOST_TEST_LOGGER=HRF,test_suite,stdout:XML,all,build/xunit-log.xml
 
 # Run unit tests
-./build/unit-tests $(ut_log_args)
+./build/unit-tests