exabayes: specify c++11 (#30282)

var/spack/repos/builtin/packages/exabayes/package.py

@@ -35,3 +35,9 @@ def configure_args(self):
         else:
             args.append('--disable-mpi')
         return args
+
+    def flag_handler(self, name, flags):
+        if name.lower() == 'cxxflags':
+            # manual cites need for c++11
+            flags.append(self.compiler.cxx11_flag)
+        return (flags, None, None)