Fixes an error with -pedantic -std=c99 and GCC 4.7.2: ‘visibility’ attribute ignored on types

include/assimp/material.h

@@ -657,7 +657,7 @@ struct aiMaterialProperty
 *  have to stick with the aiMaterialGetXXX family of unbound functions.
 *  The library defines a set of standard keys (AI_MATKEY_XXX).
 */
-struct ASSIMP_API aiMaterial
+struct aiMaterial
 {
 
 #ifdef __cplusplus