Hint to -fno-gnu-unique

Author: Andreas Junghanns

fmi-guide/3___packaging.adoc

@@ -167,6 +167,8 @@ Furthermore, in case of failure, automatic linking is unlikely to provide user-u
 Note that simple calls to `LoadLibrary` or `LoadLibraryEx` on Windows, without specifying the full path to the library are also not going to work in general, for the same reasons:
 The search path will be based on the location of the importer executable and not the FMU DLL.
 
+Note also that on Linux, `dlclose` is not guaranteed to unload the shared object with newer compilers and might require the compiler flag `-fno-gnu-unique` to enforce actual unloading of the shared object.
+
 === Interaction between FMU and Importer
 
 The FMU code will run in the process environment that the importer provides.