math_opt: fixup

ortools/math_opt/cpp/CMakeLists.txt

@@ -16,7 +16,7 @@ add_library(${NAME} OBJECT)
 
 file(GLOB _SRCS "*.h" "*.cc")
 list(FILTER _SRCS EXCLUDE REGEX ".*_test.cc")
-list(FILTER _SRCS EXCLUDE REGEX "/matchers\\.")
+list(FILTER _SRCS EXCLUDE REGEX "/matchers\.")
 
 target_sources(${NAME} PRIVATE ${_SRCS})
 set_target_properties(${NAME} PROPERTIES POSITION_INDEPENDENT_CODE ON)

ortools/math_opt/cpp/key_types.h

@@ -149,17 +149,17 @@ std::vector<typename Map::mapped_type> Values(const Map& map,
 namespace internal {
 
 // The CHECK message to use when a KeyType::storage() is nullptr.
-inline const std::string kKeyHasNullModelStorage =
+inline constexpr const char kKeyHasNullModelStorage[] =
     "The input key has null .storage().";
 
 // The CHECK message to use when two KeyType with different storage() are used
 // in the same collection.
-inline const std::string kObjectsFromOtherModelStorage =
+inline constexpr const char kObjectsFromOtherModelStorage[] =
     "The input objects belongs to another model.";
 
 // The Status message to use when an input KeyType is from an unexpected
 // storage().
-inline constexpr absl::string_view kInputFromInvalidModelStorage =
+inline constexpr const char kInputFromInvalidModelStorage[] =
     "the input does not belong to the same model";
 
 // Returns a failure when the input pointer is not nullptr and points to a