regtest: add -std=c++17 for memcheck xmas_tree

For middle-aged compilers that support C++17 but not by default.

diff --git a/memcheck/tests/Makefile.am b/memcheck/tests/Makefile.am
index 89937a7cb8b7f39982f5918cd7933ec44492adbf..88e995cde9fc61510524d3d4073da228e14f4f8a 100644 (file)
--- a/memcheck/tests/Makefile.am
+++ b/memcheck/tests/Makefile.am
@@ -978,4 +978,4 @@ writev1_CFLAGS              = $(AM_CFLAGS) @FLAG_W_NO_STRINGOP_OVERFLOW@ @FLAG_W_NO_STRINGOP
 xml1_CFLAGS             = $(AM_CFLAGS) -D_GNU_SOURCE @FLAG_W_NO_UNINITIALIZED@ @FLAG_W_NO_USE_AFTER_FREE@
 
 xmas_tree_SOURCES      = xmas_tree.cpp
-xmas_tree_CXXFLAGS     = ${AM_CXXFLAGS} @FLAG_W_NO_UNINITIALIZED@ @FLAG_W_NO_MISMATCHED_NEW_DELETE@ @FLAG_W_ALLOC_SIZE_LARGER_THAN@
+xmas_tree_CXXFLAGS     = ${AM_CXXFLAGS} -std=c++17 @FLAG_W_NO_UNINITIALIZED@ @FLAG_W_NO_MISMATCHED_NEW_DELETE@ @FLAG_W_ALLOC_SIZE_LARGER_THAN@