or-tools: fix string_view compilation issue (#258332)

Fixes #256266
Don't use non-existent member function on string_view.
(StringPiece and string_view are almost the same looks like they
are typedef'd to the same string_view. StringPiece used to have
a as_string() member)

pkgs/development/libraries/science/math/or-tools/default.nix

@@ -45,6 +45,9 @@ stdenv.mkDerivation rec {
       url = "https://github.com/google/or-tools/commit/edd1544375bd55f79168db315151a48faa548fa0.patch";
       hash = "sha256-S//1YM3IoRCp3Ghg8zMF0XXgIpVmaw4gH8cVb9eUbqM=";
     })
+    # Don't use non-existent member of string_view. Partial patch from commit
+    # https://github.com/google/or-tools/commit/c5a2fa1eb673bf652cb9ad4f5049d054b8166e17.patch
+    ./fix-stringview-compile.patch
   ];
 
   # or-tools normally attempts to build Protobuf for the build platform when

pkgs/development/libraries/science/math/or-tools/fix-stringview-compile.patch

@@ -0,0 +1,36 @@
+diff --git a/ortools/lp_data/lp_parser.cc b/ortools/lp_data/lp_parser.cc
+index 58286306e5..bd26c019ab 100644
+--- a/ortools/lp_data/lp_parser.cc
++++ b/ortools/lp_data/lp_parser.cc
+@@ -185,7 +185,7 @@ bool LPParser::ParseIntegerVariablesList(StringPiece line) {
+
+ bool LPParser::ParseConstraint(StringPiece constraint) {
+   const StatusOr<ParsedConstraint> parsed_constraint_or_status =
+-      ::operations_research::glop::ParseConstraint(constraint.as_string());
++      ::operations_research::glop::ParseConstraint(constraint);
+   if (!parsed_constraint_or_status.ok()) return false;
+   const ParsedConstraint& parsed_constraint =
+       parsed_constraint_or_status.value();
+@@ -342,10 +342,9 @@ TokenType LPParser::ConsumeToken(StringPiece* sp) {
+
+ }  // namespace
+
+-StatusOr<ParsedConstraint> ParseConstraint(absl::string_view constraint_view) {
++StatusOr<ParsedConstraint> ParseConstraint(absl::string_view constraint) {
+   ParsedConstraint parsed_constraint;
+   // Get the name, if present.
+-  StringPiece constraint{constraint_view};
+   StringPiece constraint_copy{constraint};
+   std::string consumed_name;
+   Fractional consumed_coeff;
+@@ -413,8 +412,8 @@ StatusOr<ParsedConstraint> ParseConstraint(absl::string_view constraint_view) {
+     right_bound = consumed_coeff;
+     if (ConsumeToken(&constraint, &consumed_name, &consumed_coeff) !=
+         TokenType::END) {
+-      return absl::InvalidArgumentError(absl::StrCat(
+-          "End of input was expected, found: ", constraint.as_string()));
++      return absl::InvalidArgumentError(
++          absl::StrCat("End of input was expected, found: ", constraint));
+     }
+   }
+