- When using CPATH, we only need -isysroot and not the other -I spam.
- LDFLAGS use -isysroot instead of -L
Turns out that the linker also understands the
-isysroot flag which behaves more natural (in the
sense: "like the internal defaults `/usr/lib` etc.)
than adding `-L$(SDKROOT).
Especially for duplicates, the linker first searches
through all `-L` dirs and then looks at the sysroot
or internal defaults. This is what we want.
- Pkg-config needs CC with CFLAGS passed to configure.
ClosesHomebrew/homebrew#14351.
Signed-off-by: Jack Nagel <jacknagel@gmail.com>