config.tests/unix/icu fails for static icu

I want to link statically the Qt dependencies of my Qt build. Therefore i build icu statically and provided the -icu configuration flag. Using icu as a shared lib runs fine, but in the static case the Qt build configuration fails with the following message:

ERROR: Feature 'icu' was enabled, but the pre-condition 'libs.icu' failed.

I looked up the specific configuration test location in qt5/qtbase/config.tests/unix/icu. Running the already correctly configured make shows the following errors:

/home/myUser/.conan/data/icu/57.1/annulen/stable/package/4cc931e24e37948d83aaaf638aeca02991ff6d08/lib/libicuuc.a(putil.ao):putil.cpp:function uprv_dl_open_57: error: undefined reference to 'dlopen'
/home/myUser/.conan/data/icu/57.1/annulen/stable/package/4cc931e24e37948d83aaaf638aeca02991ff6d08/lib/libicuuc.a(putil.ao):putil.cpp:function uprv_dl_close_57: error: undefined reference to 'dlclose'
/home/myUser/.conan/data/icu/57.1/annulen/stable/package/4cc931e24e37948d83aaaf638aeca02991ff6d08/lib/libicuuc.a(putil.ao):putil.cpp:function uprv_dlsym_func_57: error: undefined reference to 'dlsym'
collect2: Fehler: ld gab 1 als Ende-Status zurück

I searched for the missing symbol problem and found this stack overflow post:
http://stackoverflow.com/questions/956640/linux-c-error-undefined-reference-to-dlopen

Using the additional -ldl flag for the LIBS in the preconfigured makefile seems to fix the problem and the build process exits without any warning or error.

So my specific questions are:

1. Is Qt able to handle static icu linking into the Qt lib?
2. Is only the config test broken by the missing -ldl flag for the static case?
3. What should i do to be able to statically link every Qt dependency into the Qt itself?