Docs: add GL_CFLAGS to GTK_DOC_CFLAGS

Otherwise introspection may fail because wayland-client.h cannot be found.
16 jobs for 1.16 in 76 minutes and 42 seconds (queued for 1 second)
latest
Status Job ID Name Coverage
  Preparation
passed #367605
gst indent

00:00:31

passed #367604
manifest

00:00:38

 
  Build
passed #367606
build fedora x86_64

00:04:32

passed #367607
build nodebug fedora x86_64

00:07:15

 
  Test
passed #367608
check fedora

00:04:02

passed #367609
integration testsuites fedora

00:08:42

 
  Full Builds
failed #367611
build cerbero android universal

01:00:01

passed #367612
build cerbero cross win32

00:39:21

passed #367613
build cerbero cross win64

00:37:22

passed #367610
build cerbero fedora x86_64

00:37:07

 
  Full Tests
skipped #367617
valgrind bad
skipped #367614
valgrind base
skipped #367618
valgrind ges
skipped #367615
valgrind good
skipped #367616
valgrind ugly
 
  Apps
skipped #367619
android universal examples
 
Name Stage Failure
failed
build cerbero android universal Full Builds The script exceeded the maximum execution time set for the job
0:46:37 [(60/79) openssl -> extract ]
0:46:37 -----> Extracting tarball to /builds/mgorse1/gst-plugins-base/cerbero-build/sources/android_universal/armv7/openssl-1.1.1
0:46:39 -----> Extracting tarball to /builds/mgorse1/gst-plugins-base/cerbero-build/sources/android_universal/arm64/openssl-1.1.1
0:46:41 -----> Extracting tarball to /builds/mgorse1/gst-plugins-base/cerbero-build/sources/android_universal/x86/openssl-1.1.1
0:46:43 -----> Extracting tarball to /builds/mgorse1/gst-plugins-base/cerbero-build/sources/android_universal/x86_64/openssl-1.1.1
0:46:45 [(60/79) openssl -> configure ]
0:46:47 [(60/79) openssl -> compile ]
Pulling docker image gitlab/gitlab-runner-helper:x86_64-ac2a293c ...
ERROR: Job failed: execution took longer than 1h0m0s seconds