Update linear solver build (#4945)

ortools/algorithms/python/BUILD.bazel

@@ -13,33 +13,11 @@
 
 # Description: python wrapping of the libraries in ../
 
-load("@bazel_skylib//rules:common_settings.bzl", "bool_flag")
 load("@pip_deps//:requirements.bzl", "requirement")
 load("@pybind11_bazel//:build_defs.bzl", "pybind_extension")
 load("@rules_cc//cc:cc_library.bzl", "cc_library")
 load("@rules_python//python:py_test.bzl", "py_test")
 
-# OSS solvers
-bool_flag(
-    name = "with_cbc",
-    build_setting_default = False,
-)
-
-config_setting(
-    name = "use_cbc",
-    flag_values = {":with_cbc": "true"},
-)
-
-bool_flag(
-    name = "with_scip",
-    build_setting_default = True,
-)
-
-config_setting(
-    name = "use_scip",
-    flag_values = {":with_scip": "true"},
-)
-
 # knapsack_solver
 cc_library(
     name = "knapsack_solver_doc",
@@ -50,13 +28,6 @@ cc_library(
 pybind_extension(
     name = "knapsack_solver",
     srcs = ["knapsack_solver.cc"],
-    copts = select({
-        ":use_cbc": ["-DUSE_CBC"],
-        "//conditions:default": [],
-    }) + select({
-        ":use_scip": ["-DUSE_SCIP"],
-        "//conditions:default": [],
-    }),
     visibility = ["//visibility:public"],
     deps = [
         ":knapsack_solver_doc",

ortools/algorithms/python/knapsack_solver.cc

@@ -67,19 +67,15 @@ PYBIND11_MODULE(knapsack_solver, m) {
              KnapsackSolver::SolverType::KNAPSACK_DYNAMIC_PROGRAMMING_SOLVER,
              DOC(operations_research, KnapsackSolver, SolverType,
                  KNAPSACK_DYNAMIC_PROGRAMMING_SOLVER))
-#if defined(USE_CBC)
       .value("KNAPSACK_MULTIDIMENSION_CBC_MIP_SOLVER",
              KnapsackSolver::SolverType::KNAPSACK_MULTIDIMENSION_CBC_MIP_SOLVER,
              DOC(operations_research, KnapsackSolver, SolverType,
                  KNAPSACK_MULTIDIMENSION_CBC_MIP_SOLVER))
-#endif  // USE_CBC
-#if defined(USE_SCIP)
       .value(
           "KNAPSACK_MULTIDIMENSION_SCIP_MIP_SOLVER",
           KnapsackSolver::SolverType::KNAPSACK_MULTIDIMENSION_SCIP_MIP_SOLVER,
           DOC(operations_research, KnapsackSolver, SolverType,
               KNAPSACK_MULTIDIMENSION_SCIP_MIP_SOLVER))
-#endif  // USE_SCIP
       .value("KNAPSACK_DIVIDE_AND_CONQUER_SOLVER",
              KnapsackSolver::SolverType::KNAPSACK_DIVIDE_AND_CONQUER_SOLVER,
              DOC(operations_research, KnapsackSolver, SolverType,