Fix unused platform check and configuration for macOS
In a similar manner as zlib (https://github.com/madler/zlib/pull/895),
libpng contains a header configuration that's no longer valid and
hasn't been exercised for the macOS target.
- The target OS conditional macros are misused. Specifically
`TARGET_OS_MAC` covers all Apple targets, including iOS, and it
should not be checked with `#if defined` as they would always be
defined (to either 1 or 0) on Apple platforms.
- `#include <fp.h>` no longer works for the macOS target and results
in a compilation failure. macOS ships all required functions in
`math.h`, and clients should use `math.h` instead.
This problem has not been noticed until a recent extension in clang
(https://github.com/llvm/llvm-project/pull/74676) exposed the issue
and broke libpng builds on Apple platforms. The failure can be
reproduced now by adding `#include <TargetConditionals.h>` before the
block.
Signed-off-by: Cosmin Truta <ctruta@gmail.com>
2 files changed
