g++ will not link to library in /usr/lib/

I've created a library and installed it in /usr/lib (using cmake) eg.:

set(CMAKE_INSTALL_PREFIX /usr/) target_link_libraries(ssd1306)set_target_properties(ssd1306 PROPERTIES   VERSION 1.0.0   SOVERSION 1 )install(TARGETS ssd1306 DESTINATION lib)   install(FILES ${SSD1306_HEADERS} DESTINATION include)

This worked fine and the library is present on my filesystem:The library:

ls -l /usr/lib/libssd1306*

/usr/lib/libssd1306.so -> libssd1306.so.1/usr/lib/libssd1306.so.1 -> libssd1306.so.1.0.0/usr/lib/libssd1306.so.1.0.0

And the header:

ls -l /usr/include/ssd1306.h

/usr/include/ssd1306.h

Then I wrote a program which use the library (again using cmake):

target_link_libraries(ssd1306-info libssd1306)

But for some reason it will not link to my library at compile time:

/usr/bin/ld: cannot find -llibssd1306

The header file was found and the object file was created, but linking failed.

Of course /usr/lib/ is in g++ search path:

g++ -print-search-dirs

install: /usr/lib/gcc/x86_64-linux-gnu/5/programs: =/usr/lib/gcc/x86_64-linux-gnu/5/:/usr/lib/gcc/x86_64-linux-gnu/5/:/usr/lib/gcc/x86_64-linux-gnu/:/usr/lib/gcc/x86_64-linux-gnu/5/:/usr/lib/gcc/x86_64-linux-gnu/:/usr/lib/gcc/x86_64-linux-gnu/5/../../../../x86_64-linux-gnu/bin/x86_64-linux-gnu/5/:/usr/lib/gcc/x86_64-linux-gnu/5/../../../../x86_64-linux-gnu/bin/x86_64-linux-gnu/:/usr/lib/gcc/x86_64-linux-gnu/5/../../../../x86_64-linux-gnu/bin/libraries: =/usr/lib/gcc/x86_64-linux-gnu/5/:/usr/lib/gcc/x86_64-linux-gnu/5/../../../../x86_64-linux-gnu/lib/x86_64-linux-gnu/5/:/usr/lib/gcc/x86_64-linux-gnu/5/../../../../x86_64-linux-gnu/lib/x86_64-linux-gnu/:/usr/lib/gcc/x86_64-linux-gnu/5/../../../../x86_64-linux-gnu/lib/../lib/:/usr/lib/gcc/x86_64-linux-gnu/5/../../../x86_64-linux-gnu/5/:/usr/lib/gcc/x86_64-linux-gnu/5/../../../x86_64-linux-gnu/:/usr/lib/gcc/x86_64-linux-gnu/5/../../../../lib/:/lib/x86_64-linux-gnu/5/:/lib/x86_64-linux-gnu/:/lib/../lib/:/usr/lib/x86_64-linux-gnu/5/:/usr/lib/x86_64-linux-gnu/:/usr/lib/../lib/:/usr/lib/gcc/x86_64-linux-gnu/5/../../../../x86_64-linux-gnu/lib/:/usr/lib/gcc/x86_64-linux-gnu/5/../../../:/lib/:/usr/lib/

What do I do wrong?