build: migrate to C++17

Change-Id: Ic5c01274f62556764ea96fc232cf3d835c4ab659
diff --git a/.jenkins.d/40-headers-check.sh b/.jenkins.d/40-headers-check.sh
index efc3bf9..b0f9987 100755
--- a/.jenkins.d/40-headers-check.sh
+++ b/.jenkins.d/40-headers-check.sh
@@ -17,7 +17,7 @@
 fi
 
 CXX=${CXX:-g++}
-STD=-std=c++14
+STD=-std=c++17
 CXXFLAGS="-O2 -Wall -Wno-unneeded-internal-declaration -Wno-unused-const-variable $(pkg-config --cflags libndn-cxx $PROJ)"
 INCLUDEDIR="$(pkg-config --variable=includedir $PROJ)"/$PROJ