Consider build-type when checking for bad optimization options

For single build-type generators such as unix make files check
CMAKE_CXX_FLAGS_<CONFIG> in addition CMAKE_CXX_FLAGS.  This is equivalent to
just CMAKE_CXX_FLAGS if not build-type is selected.  For multi-configuration
generators, check each configuration, and skip the test is any of them is bad.

I'd like to skip it only for the bad configs, but that would require generator
expression support in dune_add_test(CMAKE_GUARD ...).

dune/geometry/test/CMakeLists.txt

@@ -8,24 +8,49 @@ dune_add_test(SOURCES test-axisalignedcubegeometry.cc
 # https://gitlab.dune-project.org/core/dune-geometry/issues/19,
 # a.k.a. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87288
 set(ISSUE19_UNAFFECTED_GXX ON)
-if((CMAKE_CXX_COMPILER_ID STREQUAL "GNU") AND
-    (CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 8.2) AND
-    (CMAKE_CXX_COMPILER_VERSION VERSION_LESS 8.3))
-  separate_arguments(opts UNIX_COMMAND "${CMAKE_CXX_FLAGS}")
+set(issue19_affected_configs)
+function(check_compiler_issue19 config)
+  string(TOUPPER "${config}" CONFIG)
+  separate_arguments(opts UNIX_COMMAND "${CMAKE_CXX_FLAGS} ${CMAKE_CXX_FLAGS_${CONFIG}}")
   execute_process(
     COMMAND ${CMAKE_CXX_COMPILER} ${opts} -Q --help=optimizers
     OUTPUT_VARIABLE opt_settings
     ERROR_VARIABLE ignored # silence cc1 complaint about c++ options...
   )
   if(opt_settings MATCHES "-ftree-loop-vectorize[ \t]+\\[enabled\\]")
+    set(ISSUE19_UNAFFECTED_GXX OFF PARENT_SCOPE)
+    list(APPEND issue19_affected_configs "${config}")
+    set(issue19_affected_configs "${issue19_affected_configs}" PARENT_SCOPE)
+  endif()
+endfunction(check_compiler_issue19)
+if((CMAKE_CXX_COMPILER_ID STREQUAL "GNU") AND
+    (CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 8.2) AND
+    (CMAKE_CXX_COMPILER_VERSION VERSION_LESS 8.3))
+  if(CMAKE_BUILD_TYPE)
+    check_compiler_issue19("${CMAKE_BUILD_TYPE}")
+  elseif(CMAKE_CONFIGURATION_TYPES)
+    # multi-configuration generator, check each configuration and if any is
+    # bad skip test for all of them.  dune_add_test does not really allow to
+    # make the guard configuration-dependent.
+    foreach(conf IN LISTS CMAKE_CONFIGURATION_TYPES)
+      check_compiler_issue19("${conf}")
+    endforeach(conf)
+  else()
+    check_compiler_issue19("")
+  endif()
+  if(NOT ISSUE19_UNAFFECTED_GXX)
+    if(issue19_affected_configs)
+      string(REPLACE ";" ", " issue19_affected_configs "${issue19_affected_configs}")
+      set(issue19_affected_configs
+        " (Affected configurations: ${issue19_affected_configs})")
+    endif()
     message(WARNING "You are using gcc 8.2 with optimization options "
       "including -ftree-loop-vectorize (possibly implicated by -O3).  This is "
       "known to miscompile, see "
       "https://gitlab.dune-project.org/core/dune-geometry/issues/19 and "
-      "https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87288")
+      "https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87288${issue19_affected_configs}")
     message(WARNING "Skipping test-cornerstoragerefwrap due to known-bad "
-      "compiler optimization combination")
-    set(ISSUE19_UNAFFECTED_GXX OFF)
+      "compiler/optimization combination")
   endif()
 endif()
 dune_add_test(SOURCES test-cornerstoragerefwrap.cc