Add Assimp library in thirdparty

From https://github.com/assimp/assimp repo at d2b45377e4b09a1f43be95e45553afcc06b03f4b

thirdparty/assimp/code/FBXCompileConfig.h

@@ -0,0 +1,70 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2019, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** @file  FBXCompileConfig.h
+ *  @brief FBX importer compile-time switches
+ */
+#ifndef INCLUDED_AI_FBX_COMPILECONFIG_H
+#define INCLUDED_AI_FBX_COMPILECONFIG_H
+
+#include <map>
+
+//
+#if _MSC_VER > 1500 || (defined __GNUC___)
+#   define ASSIMP_FBX_USE_UNORDERED_MULTIMAP
+#   else
+#   define fbx_unordered_map map
+#   define fbx_unordered_multimap multimap
+#endif
+
+#ifdef ASSIMP_FBX_USE_UNORDERED_MULTIMAP
+#   include <unordered_map>
+#   if _MSC_VER > 1600
+#       define fbx_unordered_map unordered_map
+#       define fbx_unordered_multimap unordered_multimap
+#   else
+#       define fbx_unordered_map tr1::unordered_map
+#       define fbx_unordered_multimap tr1::unordered_multimap
+#   endif
+#endif
+
+#endif // INCLUDED_AI_FBX_COMPILECONFIG_H