Better give it a libary.json manifest in which you can nicely specify the build flags and thus the include paths.
This is indeed the issue, but you’ll have to adapt the linker flags too and that can only be done via scripting, see Changing -mfloat-abi build option not working - #2 by maxgerhardt and Unable to solve error ".o uses VFP register arguments, .elf does not" - #6 by maxgerhardt