I found in another project that using inline, inlined some functions in the
output object code. When using single file build, the implementation is defined
in one file and if it becomes inlined, then the function name is lost.
If then another file references the library and tries to use a function that has
been inlined, the linker won't be able to resolve the function name and the
object code since it has been inlined. So I've removed it from the library until
I find a case where it's suitable to use.