diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 5a3332abea..cffc7a824f 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -30,8 +30,16 @@ variables:
 
 workflow:
   rules:
-    - if: $CI_COMMIT_TAG
+    # run merge request pipelines
+    - if: $CI_PIPELINE_SOURCE == "merge_request_event"
+    # do not run branch pipelines if corresponding merge requests exist...
+    # (this avoids duplicate pipelines)
+    - if: $CI_COMMIT_BRANCH && $CI_OPEN_MERGE_REQUESTS
+      when: never
+    # ...but otherwise run branch pipelines
     - if: $CI_COMMIT_BRANCH
+    # run tag pipelines
+    - if: $CI_COMMIT_TAG
 
 default:
   retry:
@@ -197,28 +205,44 @@ msys2-mingw64:
     paths:
       - "${CI_PROJECT_DIR}/_build/gtkdll.tar.gz"
 
-macos:
-  # Sadly, this fails regularly, and its failure is never enlightening
-  allow_failure: true
+macos-x86_64:
   rules:
+    # Do not run in forks as the runner is not available there.
     - if: $CI_PROJECT_NAMESPACE == "GNOME"
   stage: build
   tags:
-    - macos
+    - macosintel
   needs: []
+  variables:
+    MESON_FORCE_BACKTRACKE: 1
+    TMPDIR: /Users/Shared/work/tmp
+    SDKROOT: /opt/sdks/MacOSX10.13.4.sdk
+    PIP_CACHE_DIR: /Users/Shared/build/cache
+    PIPENV_CACHE_DIR: $PIP_CACHE_DIR
+    PYTHONPYCACHEPREFIX: $PIP_CACHE_DIR
+    EXTRA_MESON_FLAGS: "-Dgobject-introspection:werror=false"
   before_script:
+    # Not using ccache on purpose as it accelerates the build so much that it
+    # can trigger race conditions in the gobject-introspection subproject.
     - bash .gitlab-ci/show-info-osx.sh
-    - pip3 install --user meson~=1.0
-    - pip3 install --user ninja
-    - export PATH=/Users/gitlabrunner/Library/Python/3.7/bin:$PATH
-    - export MESON_FORCE_BACKTRACE=1
+    - /opt/macports/bin/python3.10 -m venv .venv
+    - ln -s /opt/cmake/CMake.app/Contents/bin/cmake .venv/bin
+    - ln -s /opt/pkg-config/bin/pkg-config .venv/bin
+    - ln -s /opt/bison/bin/bison .venv/bin
+    - source .venv/bin/activate
+    - pip3 install meson==1.2.0
+    - pip3 install ninja==1.11.1
+    - pip3 install /Users/Shared/build/pkgs/PyGObject-3.44.0-cp310-cp310-macosx_10_13_x86_64.whl
+                   /Users/Shared/build/pkgs/pycairo-1.23.0-cp310-cp310-macosx_10_13_x86_64.whl
   script:
-    - meson setup ${COMMON_MESON_FLAGS}
+    - meson setup
+            ${COMMON_MESON_FLAGS}
+            ${EXTRA_MESON_FLAGS}
             -Dx11-backend=false
             -Dbroadway-backend=true
             -Dmacos-backend=true
             -Dmedia-gstreamer=disabled
-            -Dintrospection=disabled
+            -Dintrospection=enabled
             -Dcpp_std=c++11
             -Dpixman:tests=disabled
             -Dlibjpeg-turbo:simd=disabled
diff --git a/gdk/macos/gdkmacosglcontext-private.h b/gdk/macos/gdkmacosglcontext-private.h
index 4e83e5cb0e..95966a4c12 100644
--- a/gdk/macos/gdkmacosglcontext-private.h
+++ b/gdk/macos/gdkmacosglcontext-private.h
@@ -27,9 +27,7 @@
 #include "gdkmacosdisplay.h"
 #include "gdkmacossurface.h"
 
-#import <OpenGL/OpenGL.h>
-#import <OpenGL/gl3.h>
-#import <AppKit/AppKit.h>
+#import <epoxy/gl.h>
 
 G_BEGIN_DECLS
 
diff --git a/gdk/macos/gdkmacosglcontext.c b/gdk/macos/gdkmacosglcontext.c
index 87e6e19fe0..a706a407b5 100644
--- a/gdk/macos/gdkmacosglcontext.c
+++ b/gdk/macos/gdkmacosglcontext.c
@@ -21,7 +21,6 @@
 
 #include "gdkconfig.h"
 
-#include <OpenGL/gl3.h>
 #include <OpenGL/CGLIOSurface.h>
 #include <QuartzCore/QuartzCore.h>
 
@@ -499,7 +498,7 @@ gdk_macos_gl_context_begin_frame (GdkDrawContext *context,
   gdk_gl_context_make_current (GDK_GL_CONTEXT (self));
   gdk_macos_gl_context_allocate (self);
 
-  GDK_DRAW_CONTEXT_CLASS (gdk_macos_gl_context_parent_class)->begin_frame (context, prefers_high_depth, region);
+  GDK_DRAW_CONTEXT_CLASS (gdk_macos_gl_context_parent_class)->begin_frame (context, depth, region);
 
   gdk_gl_context_make_current (GDK_GL_CONTEXT (self));
   CHECK_GL (NULL, glBindFramebuffer (GL_FRAMEBUFFER, self->fbo));
diff --git a/gdk/macos/gdkmacosmonitor.c b/gdk/macos/gdkmacosmonitor.c
index df2676b6cf..b1bf0b1f11 100644
--- a/gdk/macos/gdkmacosmonitor.c
+++ b/gdk/macos/gdkmacosmonitor.c
@@ -331,7 +331,7 @@ _gdk_macos_monitor_reconfigure (GdkMacosMonitor *self)
   gdk_monitor_set_physical_size (GDK_MONITOR (self), width_mm, height_mm);
   gdk_monitor_set_scale_factor (GDK_MONITOR (self), scale_factor);
   gdk_monitor_set_refresh_rate (GDK_MONITOR (self), refresh_rate);
-  gdk_monitor_set_subpixel_layout (GDK_MONITOR (self), GDK_SUBPIXEL_LAYOUT_UNKNOWN);
+  gdk_monitor_set_subpixel_layout (GDK_MONITOR (self), subpixel_layout);
 
   self->workarea = [screen visibleFrame];