Toolchain: Add CMAKE_PLATFORM_USES_PATH_WHEN_NO_SONAME to Platform

This property tells CMake that if a library is missing a SONAME field,
the link editor(s) we use will insert the full path to the library into
the binary. This is the behaivor of GNU ld compatible linkers, so let's
avoid that possiblity by telling CMake that it really doesn't want to
let the linker embed the full path to the lib. This is especially
important when cross-compiling things for ports and such, as the full
path to the lib will have absolutely nothing to do with the runtime path

Toolchain/CMake/Platform/SerenityOS.cmake

@@ -8,6 +8,10 @@ set(CMAKE_EXE_EXPORTS_C_FLAG "-Wl,--export-dynamic")
 set(CMAKE_SHARED_LIBRARY_SUFFIX ".so")
 set(CMAKE_SHARED_LIBRARY_CREATE_CXX_FLAGS "-shared -Wl,--hash-style=gnu,-z,relro,-z,now,-z,noexecstack,-z,separate-code")
 
+# Shared libraries with no builtin soname may not be linked safely by
+# specifying the file path.
+set(CMAKE_PLATFORM_USES_PATH_WHEN_NO_SONAME 1)
+
 # Initialize C link type selection flags.  These flags are used when
 # building a shared library, shared module, or executable that links
 # to other libraries to select whether to use the static or shared