Earlier quoted context omitted.
That's just dangerous band-aid. If there is a mismatch between bundled .h and installed system library, you'll get (in better case) linker error, or runtime problems.
Well I was assuming the actual library would be bundled too: not just the headers!
(Nb I’m a maintainer of a python project that’s difficult to build, and the number of issues we get that start: can’t install because foo.h can’t be found is very high, even though there’s other explanations closer to the end of the failed build)