build: switch to C++17

Change-Id: I92039300ce845de0312dceccb94c128229ed60c4
diff --git a/.waf-tools/default-compiler-flags.py b/.waf-tools/default-compiler-flags.py
index 5f2d0b3..8c71871 100644
--- a/.waf-tools/default-compiler-flags.py
+++ b/.waf-tools/default-compiler-flags.py
@@ -139,7 +139,7 @@
     """
     def getGeneralFlags(self, conf):
         flags = super(GccBasicFlags, self).getGeneralFlags(conf)
-        flags['CXXFLAGS'] += ['-std=c++14']
+        flags['CXXFLAGS'] += ['-std=c++17']
         if Utils.unversioned_sys_platform() != 'darwin':
             flags['LINKFLAGS'] += ['-fuse-ld=lld']
         return flags