Disable dump when export is not supported.

tools/assimp_cmd/WriteDump.cpp

@@ -66,6 +66,8 @@ const char *AICMD_MSG_DUMP_HELP =
 FILE *out = nullptr;
 bool shortened = false;
 
+#ifndef ASSIMP_BUILD_NO_EXPORT
+
 // -----------------------------------------------------------------------------------
 int Assimp_Dump(const char *const *params, unsigned int num) {
     const char *fail = "assimp dump: Invalid number of arguments. "
@@ -162,3 +164,9 @@ int Assimp_Dump(const char *const *params, unsigned int num) {
     printf("assimp dump: Wrote output dump %s\n", cur_out.c_str());
     return AssimpCmdError::Success;
 }
+#else
+int Assimp_Dump(const char *const *, unsigned int ) {
+    printf("assimp dump: Export disabled.\n");
+    return AssimpCmdError::UnrecognizedCommand;
+}
+#endif