FindPackageModeMakefileTest: macOS needs isysroot flag
macOS/Xcode no longer populate /usr/include
. Building with the compiler directly instead of using /usr/bin/c++
can result in missing headers without the -isysroot
flag.
This technically fixes the immediate test failure reported in #19885, but that issue also mentions subsequent linker warnings that will probably become hard errors in a future macOS/Xcode version.