Added AND condition in poly2tri dll_symbol.h to only define macros fo… (#5693)

* Added ADD condition in poly2tri dll_symbol.h to only define macros for dynamic library linking if assimp is ordered to build as DLL

* Reverted last commit to handle this issue in a better way.

* added P2T_STATIC_EXPORTS to compile definitions when building assimp as DLL

---------

Co-authored-by: Kim Kulling <[email protected]>

code/CMakeLists.txt

@@ -1334,7 +1334,7 @@ ADD_LIBRARY(assimp::assimp ALIAS assimp)
 IF (BUILD_SHARED_LIBS)
   TARGET_COMPILE_DEFINITIONS(assimp PRIVATE ASSIMP_BUILD_DLL_EXPORT)
 ELSE ()
-  TARGET_COMPILE_DEFINITIONS(assimp PRIVATE OPENDDL_STATIC_LIBARY)
+  TARGET_COMPILE_DEFINITIONS(assimp PRIVATE OPENDDL_STATIC_LIBARY P2T_STATIC_EXPORTS)
 ENDIF ()
 
 TARGET_USE_COMMON_OUTPUT_DIRECTORY(assimp)