CMake: Linking statically against libgcc and libstdc++ into a shared library

As of cmake 3.13, there is a new cmake function for general linker options:

https://cmake.org/cmake/help/v3.13/command/target_link_options.html

target_link_options(<target> [BEFORE]
  <INTERFACE|PUBLIC|PRIVATE> [items1...]
  [<INTERFACE|PUBLIC|PRIVATE> [items2...] ...])

The appropriate way to specify libraries to be linked is still:

https://cmake.org/cmake/help/v3.13/command/target_link_libraries.html

target_link_libraries(<target>
  <PRIVATE|PUBLIC|INTERFACE> <item>...
  [<PRIVATE|PUBLIC|INTERFACE> <item>...]...)

There are a few different signatures depending on whether or not you want these libraries to be propagated to dependent targets, so be sure to check the docs.

Yes, target_link_libraries is a correct way to set linker flags or linker options.

Documentation of target_link_libraries:

Specify libraries or flags to use when linking a given target.

Item names starting with -, but not -l or -framework, are treated as linker flags.

https://cmake.org/cmake/help/v3.0/command/target_link_libraries.html (emphasis not in original)