- Use %() to extract patch date for adding it to version
* add script get_version_number.sh which is used within the
spec file to determine the actual patch version date

- Add ncurses patch 20200404
+ modify -fvisibility check to work with g++
> fixes for building with Visual Studio C++ and msys2 (patches by
"Maarten Anonymous"):
+ add configure option and check for gcc -fvisibility=hidden feature
+ define NCURSES_NOMACROS in lib_gen.c to work around Visual Studio
C++ preprocessor limitations.
+ modify some of the configure-macros, as well as mk-1st.awk to work
with Visual Studio C++ default filenaming.

- Add ncurses patch 20200328
+ correct length of buffer copied in dup_field().
+ remove "$(srcdir)/" from path of library.gpr, needed for out-of-tree
builds of Ada95 (patch by Adam Van Ymeren).