build: Allow recipes to enable cmake support for meson

This was disabled as an optimisation on Windows but might be needed by
some recipes, so let's allow them to opt-in.

Part-of: <!682>
16 jobs for master in 61 minutes and 41 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Build Docker
passed alpine amd64 manifest builder docker #7862214

00:00:22

passed android docker #7862213

00:00:16

passed cerbero fedora amd64 docker #7862212

00:00:24

passed fedora amd64 docker #7862211

00:00:16

passed gst-indent amd64 docker #7862215

00:00:17

passed windows amd64 docker #7862216
windows shell 1809

00:00:09

 
  Preparation
passed manifest #7862217

00:00:14

 
  Build
passed cerbero deps cross-android universal #7862219
gstreamer

00:14:41

failed cerbero deps cross-ios universal #7862223
gst-ios-14.3

01:01:02

passed cerbero deps cross-windows x86 #7862220
gstreamer

00:05:43

passed cerbero deps cross-windows x86_64 #7862221
gstreamer

00:06:14

passed cerbero deps fedora x86_64 #7862218
gstreamer

00:05:57

passed cerbero deps macos x86_64 #7862222
gst-macos-11.1

00:48:17

passed cerbero deps msvc x86_64 #7862224
docker windows gstreamer-windows 1809

00:42:02

 
  Integrate
failed cerbero cross-android universal examples #7862225

00:01:51

skipped cerbero cross-ios universal examples #7862226
gst-ios-14.3
 
Name Stage Failure
failed
cerbero deps cross-ios universal Build
Uploading artifacts for failed job
Uploading artifacts...
Runtime platform
arch=amd64 os=darwin pid=66279 revision=943fc252 version=13.7.0
manifest.xml: found 1 matching files and directories

cerbero-build/logs: found 751 matching files and directories

WARNING: gstreamer-1.0-*-ios-universal.pkg: no matching files
Uploading artifacts as "archive" to coordinator... ok
id=7862223 responseStatus=201 Created token=H2PoXh5H
Cleaning up file based variables
ERROR: Job failed: Process exited with status 1
failed
cerbero cross-android universal examples Integrate
$ rm -rf ${GSTREAMER_ROOT_ANDROID}
$ rm -rf ${EXAMPLES_HOME}/gst-examples ${EXAMPLES_HOME}/gst-docs
Uploading artifacts for failed job
Uploading artifacts...
manifest.xml: found 1 matching files and directories

/builds/gstreamer/cerbero/examples/outputs: found 1 matching files and directories

Uploading artifacts as "archive" to coordinator... ok
id=7862225 responseStatus=201 Created token=-b7qU7EE
Cleaning up file based variables
ERROR: Job failed: exit code 1