closes https://github.com/assimp/assimp/issues/1513: fix assimp for cross compile for android

code/DefaultIOSystem.cpp

@@ -49,7 +49,6 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <assimp/ai_assert.h>
 #include <stdlib.h>
 
-
 #ifdef __unix__
 #include <sys/param.h>
 #include <stdlib.h>

code/glTF2Asset.h

@@ -88,6 +88,8 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #   endif
 #endif
 
+#include "StringUtils.h"
+
 namespace glTF2
 {
 #ifdef ASSIMP_API
@@ -239,7 +241,7 @@ namespace glTF2
             case ComponentType_UNSIGNED_BYTE:
                 return 1;
             default:
-                throw DeadlyImportError("GLTF: Unsupported Component Type " + std::to_string(t));
+                throw DeadlyImportError("GLTF: Unsupported Component Type " + to_string(t));
         }
     }
 

code/glTF2Asset.inl

@@ -258,11 +258,11 @@ Ref<T> LazyDict<T>::Retrieve(unsigned int i)
     Value &obj = (*mDict)[i];
 
     if (!obj.IsObject()) {
-        throw DeadlyImportError("GLTF: Object at index \"" + std::to_string(i) + "\" is not a JSON object");
+        throw DeadlyImportError("GLTF: Object at index \"" + to_string(i) + "\" is not a JSON object");
     }
 
     T* inst = new T();
-    inst->id = std::string(mDictId) + "_" + std::to_string(i);
+    inst->id = std::string(mDictId) + "_" + to_string(i);
     inst->oIndex = i;
     ReadMember(obj, "name", inst->name);
     inst->Read(obj, mAsset);

code/glTF2Exporter.cpp

@@ -402,7 +402,7 @@ void glTF2Exporter::ExportMaterials()
     for (unsigned int i = 0; i < mScene->mNumMaterials; ++i) {
         const aiMaterial* mat = mScene->mMaterials[i];
 
-        std::string id = "material_" + std::to_string(i);
+        std::string id = "material_" + to_string(i);
 
         Ref<Material> m = mAsset->materials.Create(id);
 

code/glTFAsset.inl

@@ -1282,7 +1282,7 @@ inline void Asset::ReadBinaryHeader(IOStream& stream)
     }
 
     AI_SWAP4(header.version);
-    asset.version = std::to_string(header.version);
+    asset.version = to_string(header.version);
     if (header.version != 1) {
         throw DeadlyImportError("GLTF: Unsupported binary glTF version");
     }