test cases: pass the c++11 std to boost-using code

Apple Clang defaults to C++03 or earlier, and boost 1.84 has started
requiring C++11 as a minimum. Fixes test failures on the macOS builders.

Unneeded for GCC systems since GCC defaults to a more recent std -- but
also semantically correct there too.

test cases/common/219 include_type dependency/meson.build

@@ -1,6 +1,7 @@
 project(
   'dependency include_type',
   ['c', 'cpp'],
+  default_options: ['cpp_std=c++11'],
 )
 
 dep = dependency('zlib', method: 'pkg-config', required : false)