libraries/Atlas-C++: Use the C++14 standard.

gcc >= 11.x defaults to -std=gnu++17 and it breaks the build
in this case

Signed-off-by: Matteo Bernardini <ponce@slackbuilds.org>

Signed-off-by: Willy Sudiarto Raharjo <willysr@slackbuilds.org>

libraries/Atlas-C++/Atlas-C++.SlackBuild

@@ -80,7 +80,7 @@ find -L . \
   -o -perm 440 -o -perm 400 \) -exec chmod 644 {} \;
 
 CFLAGS="$SLKCFLAGS" \
-CXXFLAGS="$SLKCFLAGS -Wno-error=deprecated" \
+CXXFLAGS="$SLKCFLAGS -Wno-error=deprecated -std=c++14" \
 ./configure \
   --prefix=/usr \
   --libdir=/usr/lib${LIBDIRSUFFIX} \