Fix static library build

[mertemba]

The libsocketConfig.cmake.in assumes that the library target is called socket++, but the static library is currently called socket++_int. Thus, using the static build of libsocket with FetchContent is currently broken.

This commit changes the static library target name to the same as the shared library. The drawback is that now BUILD_SHARED_LIBS and BUILD_STATIC_LIBS cannot be enabled both at the same time, because it would lead to a name collision.

[dermesser]

Thank you for reporting this. However, given that the build process has been very stable for the past few years, would it be an option to change libsocketConfig.cmake.in to set socket++_int as library to link against? That would prevent breakage for those users who currently might build both static and dynamic libraries, wouldn't it?

[mertemba]

Thank you for the quick reply. I'm no expert for ...Config.cmake.in files, but I'll try adding socket++_int or something else to make building both static and dynamic libraries work. I'll get back to you.