Build error on macOS: `utils.cpp: fatal error: sysdir.h: No such file or directory`

[barracuda156]

Describe the bug
The build unconditionally includes a header which may not exist.

To Reproduce
Run the build.

Expected behavior
SDK is respected and appropriate headers are included based on the target version.

Logs

[ 65%] Building CXX object CMakeFiles/ImPlay.dir/source/helpers/utils.cpp.o
/opt/local/bin/g++-mp-14 -DAPP_VERSION=\"0.0.0\" -DLIBROMFS_PROJECT_NAME=ImPlay -I/opt/local/var/macports/build/implay-82833586/work/ImPlay-1.5.1/include -I/opt/local/include -I/opt/local/var/macports/build/implay-82833586/work/ImPlay-1.5.1/third_party/glad/include -I/opt/local/var/macports/build/implay-82833586/work/ImPlay-1.5.1/third_party/fmt/include -I/opt/local/var/macports/build/implay-82833586/work/ImPlay-1.5.1/third_party/natsort/include -I/opt/local/var/macports/build/implay-82833586/work/ImPlay-1.5.1/third_party/json/include -I/opt/local/var/macports/build/implay-82833586/work/ImPlay-1.5.1/third_party/inipp/include -I/opt/local/var/macports/build/implay-82833586/work/ImPlay-1.5.1/third_party/nativefiledialog/src/include -I/opt/local/var/macports/build/implay-82833586/work/ImPlay-1.5.1/third_party/imgui/include -I/opt/local/include/freetype2 -I/opt/local/var/macports/build/implay-82833586/work/ImPlay-1.5.1/third_party/libromfs/lib/include -pipe -Os -DNDEBUG -I/opt/local/include -DGLFW_COMPAT -DGLFW_EXPOSE_NATIVE_NSGL -DGLFW_VERSION_COMBINED=3120 -D_GLIBCXX_USE_CXX11_ABI=0 -std=gnu++20 -arch ppc -mmacosx-version-min=10.6 -MD -MT CMakeFiles/ImPlay.dir/source/helpers/utils.cpp.o -MF CMakeFiles/ImPlay.dir/source/helpers/utils.cpp.o.d -o CMakeFiles/ImPlay.dir/source/helpers/utils.cpp.o -c /opt/local/var/macports/build/implay-82833586/work/ImPlay-1.5.1/source/helpers/utils.cpp
[ 68%] Building CXX object CMakeFiles/ImPlay.dir/source/views/view.cpp.o
/opt/local/bin/g++-mp-14 -DAPP_VERSION=\"0.0.0\" -DLIBROMFS_PROJECT_NAME=ImPlay -I/opt/local/var/macports/build/implay-82833586/work/ImPlay-1.5.1/include -I/opt/local/include -I/opt/local/var/macports/build/implay-82833586/work/ImPlay-1.5.1/third_party/glad/include -I/opt/local/var/macports/build/implay-82833586/work/ImPlay-1.5.1/third_party/fmt/include -I/opt/local/var/macports/build/implay-82833586/work/ImPlay-1.5.1/third_party/natsort/include -I/opt/local/var/macports/build/implay-82833586/work/ImPlay-1.5.1/third_party/json/include -I/opt/local/var/macports/build/implay-82833586/work/ImPlay-1.5.1/third_party/inipp/include -I/opt/local/var/macports/build/implay-82833586/work/ImPlay-1.5.1/third_party/nativefiledialog/src/include -I/opt/local/var/macports/build/implay-82833586/work/ImPlay-1.5.1/third_party/imgui/include -I/opt/local/include/freetype2 -I/opt/local/var/macports/build/implay-82833586/work/ImPlay-1.5.1/third_party/libromfs/lib/include -pipe -Os -DNDEBUG -I/opt/local/include -DGLFW_COMPAT -DGLFW_EXPOSE_NATIVE_NSGL -DGLFW_VERSION_COMBINED=3120 -D_GLIBCXX_USE_CXX11_ABI=0 -std=gnu++20 -arch ppc -mmacosx-version-min=10.6 -MD -MT CMakeFiles/ImPlay.dir/source/views/view.cpp.o -MF CMakeFiles/ImPlay.dir/source/views/view.cpp.o.d -o CMakeFiles/ImPlay.dir/source/views/view.cpp.o -c /opt/local/var/macports/build/implay-82833586/work/ImPlay-1.5.1/source/views/view.cpp
/opt/local/var/macports/build/implay-82833586/work/ImPlay-1.5.1/source/helpers/utils.cpp:13:10: fatal error: sysdir.h: No such file or directory
   13 | #include <sysdir.h>
      |          ^~~~~~~~~~
compilation terminated.
make[2]: *** [CMakeFiles/ImPlay.dir/source/helpers/utils.cpp.o] Error 1
make[2]: *** Waiting for unfinished jobs....

Environment (please complete the following information):

• OS: macOS
• Version 10.6.8