lp_data: remove support for old MSVC.

Author: Mizux

ortools/lp_data/lp_types.h

@@ -298,7 +298,7 @@ class StrictITIVector : public util_intops::StrongVector<IntType, T, Alloc> {
 
   // This allows for brace initialization, which is really useful in tests.
   // It is not 'explicit' by design, so one can do vector = {...};
-#if !defined(__ANDROID__) && (!defined(_MSC_VER) || (_MSC_VER >= 1800))
+#if !defined(__ANDROID__)
   StrictITIVector(std::initializer_list<T> init_list,
                   const Alloc& a = Alloc())  // NOLINT
       : ParentType(init_list.begin(), init_list.end(), a) {}

ortools/lp_data/sparse.cc

@@ -94,7 +94,6 @@ Fractional ComputeInfinityNormTemplate(const Matrix& matrix) {
 // --------------------------------------------------------
 SparseMatrix::SparseMatrix() : columns_(), num_rows_(0) {}
 
-#if (!defined(_MSC_VER) || (_MSC_VER >= 1800))
 SparseMatrix::SparseMatrix(
     std::initializer_list<std::initializer_list<Fractional>> init_list) {
   ColIndex num_cols(0);
@@ -113,7 +112,6 @@ SparseMatrix::SparseMatrix(
     ++row;
   }
 }
-#endif
 
 void SparseMatrix::Clear() {
   columns_.clear();

ortools/lp_data/sparse.h

@@ -30,12 +30,12 @@
 
 #include <algorithm>
 #include <cstdint>
+#include <initializer_list>
 #include <string>
 #include <vector>
 
 #include "absl/log/check.h"
 #include "absl/types/span.h"
-#include "ortools/base/types.h"
 #include "ortools/graph_base/iterators.h"
 #include "ortools/lp_data/lp_types.h"
 #include "ortools/lp_data/permutation.h"
@@ -73,15 +73,13 @@ class SparseMatrix {
   //    {1, 2, 3},
   //    {4, 5, 6},
   //    {7, 8, 9}};
-#if (!defined(_MSC_VER) || _MSC_VER >= 1800)
   SparseMatrix(
       std::initializer_list<std::initializer_list<Fractional>> init_list);
 
   // This type is neither copyable nor movable.
   SparseMatrix(const SparseMatrix&) = delete;
   SparseMatrix& operator=(const SparseMatrix&) = delete;
 
-#endif
   // Clears internal data structure, i.e. erases all the columns and set
   // the number of rows to zero.
   void Clear();