Shared libs

• How to write shared libraries

• https://gcc.gnu.org/wiki/Visibility

• OpenFST does not recognize FST type "vector" #1

gcc commandline: -fvisibility=hidden

--whole-archive

See

• https://ftp.gnu.org/old-gnu/Manuals/ld-2.9.1/html_node/ld_3.html

• https://stackoverflow.com/questions/805555/ld-linker-question-the-whole-archive-option

• https://jonathanhamberg.com/post/gcc-archive-linker-oddity/

g++ main.cc -Wl,--whole-archive -lhttp -Wl,--no-whole-archive -lhandlers

# https://jonathanhamberg.com/post/gcc-archive-linker-oddity/
target_link_options(hal PUBLIC
       -Wl,--whole-archive libhal.a -Wl,--no-whole-archive
       )