Merge bitcoin#30198: depends: qt 5.15.14 and fix macOS build with Clang 18

0a3631f depends: fix Qt macOS build with Clang 18 (fanquake)
b018bd7 depends: qt 5.15.14 (fanquake)

Pull request description:

  Also adds a patch to Qts internal libpng, to fix compilation using Clang 18, when targetting macOS. I'd like to get this patched, so we can continue working on removing `FORCE_USE_SYSTEM_CLANG` (bitcoin#30201); otherwise builds will be broken using the default Clang (`18`) on the current Ubuntu LTS (`24.04`).

  With this PR, anyone using Ubuntu 24.04 should be able to `apt install clang llvm lld`, and then cross-compile for macOS using:
  ```bash
  # clang --version
  Ubuntu clang version 18.1.3 (1)
  make -C depends HOST=arm64-apple-darwin FORCE_USE_SYSTEM_CLANG=1
  ./autogen.sh
  CONFIG_SITE=/path/to/depends/arm64-apple-darwin/share/config.site ./configure
  make
  # file src/qt/bitcoin-qt
  src/qt/bitcoin-qt: Mach-O 64-bit arm64 executable, flags:<NOUNDEFS|DYLDLINK|TWOLEVEL|WEAK_DEFINES|BINDS_TO_WEAK|PIE|HAS_TLV_DESCRIPTORS>
  ```

ACKs for top commit:
  TheCharlatan:
    ACK 0a3631f
  theuni:
    utACK 0a3631f
  hebasto:
    ACK 0a3631f, a new patch indeed fixes cross-compiling on Ubuntu 24.04 with `FORCE_USE_SYSTEM_CLANG=1`.

Tree-SHA512: 711d321b1efbb1aeef802d1d7e72fff8f4e28aa2420d19df9db6f4449fc7d281e1d08ba242ce20122dfe21129e713bd59e7e6ade0b67d7271eea18b39ceb9283

Author: fanquake

depends/packages/qt.mk

@@ -1,9 +1,9 @@
 package=qt
-$(package)_version=5.15.13
+$(package)_version=5.15.14
 $(package)_download_path=https://download.qt.io/official_releases/qt/5.15/$($(package)_version)/submodules
 $(package)_suffix=everywhere-opensource-src-$($(package)_version).tar.xz
 $(package)_file_name=qtbase-$($(package)_suffix)
-$(package)_sha256_hash=4cca51dcc1f22ceeee6b3e33cd1c3a60b14e85e24644dca3af89a2c2989ab809
+$(package)_sha256_hash=500d3b390048e9538c28b5f523dfea6936f9c2e10d24ab46580ff57d430b98be
 $(package)_linux_dependencies=freetype fontconfig libxcb libxkbcommon libxcb_util libxcb_util_render libxcb_util_keysyms libxcb_util_image libxcb_util_wm
 $(package)_qt_libs=corelib network widgets gui plugins testlib
 $(package)_linguist_tools = lrelease lupdate lconvert
@@ -20,15 +20,16 @@ $(package)_patches += duplicate_lcqpafonts.patch
 $(package)_patches += guix_cross_lib_path.patch
 $(package)_patches += fix-macos-linker.patch
 $(package)_patches += memory_resource.patch
+$(package)_patches += clang_18_libpng.patch
 $(package)_patches += utc_from_string_no_optimize.patch
 $(package)_patches += windows_lto.patch
 $(package)_patches += zlib-timebits64.patch
 
 $(package)_qttranslations_file_name=qttranslations-$($(package)_suffix)
-$(package)_qttranslations_sha256_hash=24d4c58bc2a40c0f44f59ee64af4192c7d0038c1e45af61646cfc5b65058f271
+$(package)_qttranslations_sha256_hash=5b94d1a11b566908622fcca2f8b799744d2f8a68da20be4caa5953ed63b10489
 
 $(package)_qttools_file_name=qttools-$($(package)_suffix)
-$(package)_qttools_sha256_hash=57c9794c572c4e02871f2e7581525752b0cf85ea16cfab23a4ac9ba7b39a5d34
+$(package)_qttools_sha256_hash=12061a85baf5f4de8fbc795e1d3872b706f340211b9e70962caeffc6f5e89563
 
 $(package)_extra_sources  = $($(package)_qttranslations_file_name)
 $(package)_extra_sources += $($(package)_qttools_file_name)
@@ -229,6 +230,7 @@ define $(package)_preprocess_cmds
   patch -p1 -i $($(package)_patch_dir)/qtbase-moc-ignore-gcc-macro.patch && \
   patch -p1 -i $($(package)_patch_dir)/memory_resource.patch && \
   patch -p1 -i $($(package)_patch_dir)/no_warnings_for_symbols.patch && \
+  patch -p1 -i $($(package)_patch_dir)/clang_18_libpng.patch && \
   patch -p1 -i $($(package)_patch_dir)/rcc_hardcode_timestamp.patch && \
   patch -p1 -i $($(package)_patch_dir)/duplicate_lcqpafonts.patch && \
   patch -p1 -i $($(package)_patch_dir)/utc_from_string_no_optimize.patch && \

depends/patches/qt/clang_18_libpng.patch

@@ -0,0 +1,40 @@
+fix Qt macOS build with Clang 18
+
+    See:
+    https://github.com/pnggroup/libpng/commit/893b8113f04d408cc6177c6de19c9889a48faa24.
+
+    In a similar manner as zlib (madler/zlib#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.
+
+--- a/qtbase/src/3rdparty/libpng/pngpriv.h
++++ b/qtbase/src/3rdparty/libpng/pngpriv.h
+@@ -514,18 +514,8 @@
+     */
+ #  include <float.h>
+ 
+-#  if (defined(__MWERKS__) && defined(macintosh)) || defined(applec) || \
+-    defined(THINK_C) || defined(__SC__) || defined(TARGET_OS_MAC)
+-   /* We need to check that <math.h> hasn't already been included earlier
+-    * as it seems it doesn't agree with <fp.h>, yet we should really use
+-    * <fp.h> if possible.
+-    */
+-#    if !defined(__MATH_H__) && !defined(__MATH_H) && !defined(__cmath__)
+-#      include <fp.h>
+-#    endif
+-#  else
+-#    include <math.h>
+-#  endif
++#  include <math.h>
++
+ #  if defined(_AMIGA) && defined(__SASC) && defined(_M68881)
+    /* Amiga SAS/C: We must include builtin FPU functions when compiling using
+     * MATH=68881