Qt5 CMake component fails under Xcode-10.2

[mouse07410 (Mouse)]

MacOS Mojave 10.14.4, Xcode-10.2.1, current Macports and all the ports.

File /opt/local/libexec/qt5/lib/cmake/Qt5Gui/Qt5GuiConfigExtras.cmake lists paths to find gl.h file:

set(_GL_INCDIRS "/System/Library/Frameworks/OpenGL.framework/Headers" "/System/Library/Frameworks/AGL.framework/Headers")
find_path(_qt5gui_OPENGL_INCLUDE_DIR gl.h
    PATHS ${_GL_INCDIRS}
)
if (NOT _qt5gui_OPENGL_INCLUDE_DIR)
    message(FATAL_ERROR "Failed to find \"gl.h\" in \"${_GL_INCDIRS}\".")
endif()
unset(_GL_INCDIRS)

Under Xcode-10.2.1 this is not correct - the correct location is

/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/Library/Frameworks/OpenGL.framework/Versions/A/Headers

So, this line in question should be changed to:

set(_GL_INCDIRS "/System/Library/Frameworks/OpenGL.framework/Headers" "/System/Library/Frameworks/AGL.framework/Headers" "/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/Library/Frameworks/OpenGL.framework/Versions/A/Headers")

[mouse07410 (Mouse)]

This problem continues. Now on Catalina 10.15.3 with Xcode-11.3.1.

Here's the patch that fixes it for the current, and presumably the future versions of Xcode:

--- /opt/local/libexec/qt5/lib/cmake/Qt5Gui/Qt5GuiConfigExtras.cmake.orig	2020-02-11 21:30:23.000000000 -0500
+++ /opt/local/libexec/qt5/lib/cmake/Qt5Gui/Qt5GuiConfigExtras.cmake	2020-02-11 21:32:59.000000000 -0500
@@ -1,7 +1,7 @@
 
 
 
-set(_GL_INCDIRS "/System/Library/Frameworks/OpenGL.framework/Headers" "/System/Library/Frameworks/AGL.framework/Headers")
+set(_GL_INCDIRS "/System/Library/Frameworks/OpenGL.framework/Headers" "/System/Library/Frameworks/AGL.framework/Headers" "/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/Library/Frameworks/OpenGL.framework/Versions/A/Headers")
 find_path(_qt5gui_OPENGL_INCLUDE_DIR gl.h
     PATHS ${_GL_INCDIRS}
 )

Could the port maintainers please apply it? I understand everybody is busy, but this seems to be a simple fix to evaluate in 10 months?

[chrstphrchvz (Christopher Chavez)]

@mouse07410, in general, improvements to MacPorts will have much better luck of being handled quickly if they are submitted as ​pull requests on GitHub.

I don't think MacPorts can guarantee that the location of Xcode.app will be /Applications/Xcode.app, so I don't think paths to its contents can be hardcoded exactly as suggested. Maybe MacPorts has a variable for this purpose, and/or there is a path that will be guaranteed to exist regardless of where Xcode.app is (maybe something like /Library/Developer/CommandLineTools/SDKs/…).

[mouse07410 (Mouse)]

Based on my experience of several years, the only guarantee about Xcode one can make is that it's located in /Applications/Xcode.app, and it's Command Line Tools counterpart (if installed or present - it may not be!) is in /Library/Developer/CommandLineTools.

[chrstphrchvz (Christopher Chavez)]

Xcode being installed to /Applications/Xcode.app, although typical, is not universally the case. The user is free to place Xcode wherever and then select it with sudo xcode-select -s /path/to/Xcode.app. A common use case is to switch between multiple Xcode versions; GitHub Actions CI offers multiple Xcode versions located in /Applications, see e.g. ​https://github.com/actions/virtual-environments/blob/fcb51fb/images/macos/macos-10.15-Readme.md#xcode.

[nilason (Nicklas Larsson)]

I just encountered this problem while trying to update orfeotoolbox, with macOS 12.6.6, Xcode 14.2 (and with qt5-qtbase @5.15.10_1 installed).

CMake Error at /opt/local/libexec/qt5/lib/cmake/Qt5Gui/Qt5GuiConfigExtras.cmake:9 (message):
  Failed to find "gl.h" in
  "/System/Library/Frameworks/OpenGL.framework/Headers;/System/Library/Frameworks/AGL.framework/Headers".
Call Stack (most recent call first):
  /opt/local/lib/cmake/Qt5Gui/Qt5GuiConfig.cmake:227 (include)
  Modules/ThirdParty/Qt/otb-module-init.cmake:23 (find_package)
  CMake/OTBModuleEnablement.cmake:273 (include)
  CMakeLists.txt:354 (include)