Fix iconv dependency export in CMake config file

Author: kmilos

src/CMakeLists.txt

@@ -284,9 +284,9 @@ endif()
 if(Iconv_FOUND AND Iconv_LIBRARIES)
   target_link_libraries(exiv2lib PRIVATE Iconv::Iconv)
   list(APPEND libs_private_list "iconv")
-  set(EXV_HAVE_LIBICONV TRUE PARENT_SCOPE)
+  set(EXV_HAVE_LIBICONV TRUE)
 else()
-  set(EXV_HAVE_LIBICONV FALSE PARENT_SCOPE)
+  set(EXV_HAVE_LIBICONV FALSE)
 endif()
 
 if(EXIV2_ENABLE_INIH)