Looks like the Ubuntu pkg-config files for Tcl/Tk are buggy; they don't provide the correct --libs flags (-L is wrong).

Resolved in commit a8313a1

Now we've got problems on FreeBSD (14.0): X11/Xlib.h is included by tk.h, X11 include path is not passed toCFLAGS:

$ grep -A5 "cc.*tcl" config.log
configure:12411: cc -o conftest  -I/usr/local/include/tcl8.6 -I/usr/local/include/tk8.6    conftest.c -L/usr/local/lib -ltk86 -ltkstub86 -ltcl86 -ltclstub86   >&5
In file included from conftest.c:111:
/usr/local/include/tk8.6/tk.h:99:13: fatal error: 'X11/Xlib.h' file not found
#   include <X11/Xlib.h>
            ^~~~~~~~~~~~

1 error generated.

$ pkg-config --libs --cflags tcl86 tk86
-I/usr/local/include/tcl8.6 -I/usr/local/include/tk8.6 -L/usr/local/lib -ltk86 -ltkstub86 -ltcl86 -ltclstub86

Proposed solution: add special case for FreeBSD in 72cf592

(I squeezed 46e43dc, 5156b57, and 8af1b25 into 72cf592)

🤖 New build scheduled with the buildbot fleet by @erlend-aasland for commit ea426ef 🤖

If you want to schedule another build, you need to add the "🔨 test-with-buildbots" label again.

Non-Windows buildbot status embedded below (updating this post at irregular intervals)

TL;DR: macOS and RHEL7 buildbots did no longer build _tkinter (change in behaviour).

There were some other issues which have been addressed:

• A FreeBSD bot failed because the X11 check lacked a guard. Addressed in 5816799

Sparked by Ronald's comment on Discourse:

We could add a hack for macOS... I added this on my macOS 12 install, and it works for me. Not sure how it would fare on older installs, though.

--- a/configure.ac
+++ b/configure.ac
@@ -3515,8 +3515,21 @@ for _QUERY in \
 done
 
 AS_VAR_IF([found_tcltk], [no], [
-  TCLTK_CFLAGS=${TCLTK_CFLAGS-""}
-  TCLTK_LIBS=${TCLTK_LIBS-""}
+  AS_CASE([$ac_sys_system],
+    [Darwin*], [
+      TCLTK_CFLAGS=${TCLTK_CFLAGS-"\
+        -I/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/Library/Frameworks/Tcl.framework/Headers \
+        -I/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/Library/Frameworks/Tk.framework/Headers \
+        -F/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/Library/Frameworks \
+      "}
+      TCLTK_LIBS=${TCLTK_LIBS-"\
+        -Wl,-F,/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/Library/Frameworks,-framework,Tcl,-framework,Tk
+      "}
+    ], [
+      TCLTK_CFLAGS=${TCLTK_CFLAGS-""}
+      TCLTK_LIBS=${TCLTK_LIBS-""}
+    ]
+  )
 ])
 
 dnl FreeBSD has an X11 dependency which is not implicitly resolved.

I'm not sure if it's worth it adding a more complex hack, or if it's worth it adding this hack in the first place.

cc. @tiran @ronaldoussoren @ned-deily

We could add a hack for macOS... I added this on my macOS 12 install, and it works for me. Not sure how it would fare on older installs, though.

Based on comments from Ned and Ronald, I'm dropping adding any hack for macOS; those building on macOS will have to install MacPorts or Homebrew, and explicitly or implicitly pass this information to configure, for example through PKG_CONFIG_PATH.

Updated to reduce configure noise.

We can now remove macosx_sdk_specified and find_library_file from setup.py. I'll push that; sorry for touching the PR again :)

Synced with main to get Serhiy's commits (GH-31839, GH-31938)

@tiran, do you want another round through the buildbots after I pulled Serhiy's changes? Apart from that, are you fine with this PR as it stands?

Thanks for the PR! I'd like to review and play with it a bit but I likely won't be able to do so before Monday. If you don't hear anything by then, go ahead.

@ned-deily would you still like to review this?

Ready to go

Ready to go

Great, thank you for reviewing! @tiran, can you land this? :)

Love it! Your PR removes a lot of complicated code from setup.py.