[INIT] move VersionString code to base/version

ortools/base/version.cc

@@ -13,10 +13,18 @@
 
 #include <string>
 
+#include "absl/strings/str_cat.h"
+
 namespace operations_research {
 
 int OrToolsMajorVersion() { return OR_TOOLS_MAJOR; }
+
 int OrToolsMinorVersion() { return OR_TOOLS_MINOR; }
+
 int OrToolsPatchVersion() { return OR_TOOLS_PATCH; }
 
+std::string OrToolsVersionString() {
+  return absl::StrCat(OR_TOOLS_MAJOR, ".", OR_TOOLS_MINOR, ".", OR_TOOLS_PATCH);
+}
+
 }  // namespace operations_research

ortools/base/version.h

@@ -14,12 +14,18 @@
 #ifndef OR_TOOLS_BASE_VERSION_H_
 #define OR_TOOLS_BASE_VERSION_H_
 
+#include <string>
+
 namespace operations_research {
 
 int OrToolsMajorVersion();
+
 int OrToolsMinorVersion();
+
 int OrToolsPatchVersion();
 
+std::string OrToolsVersionString();
+
 }  // namespace operations_research
 
 #endif  // OR_TOOLS_BASE_VERSION_H_

ortools/init/init.h

@@ -18,7 +18,6 @@
 #include <vector>
 
 #include "absl/flags/flag.h"
-#include "absl/strings/str_cat.h"
 #include "ortools/base/logging.h"
 #include "ortools/base/version.h"
 #include "ortools/gurobi/environment.h"
@@ -153,9 +152,7 @@ class OrToolsVersion {
    * Returns the string version of OR-Tools.
    */
   static std::string VersionString() {
-    return absl::StrCat(::operations_research::OrToolsMajorVersion(), ".",
-                        ::operations_research::OrToolsMinorVersion(), ".",
-                        ::operations_research::OrToolsPatchVersion(), ".");
+    return ::operations_research::OrToolsVersionString();
   }
 };