meson: error out in script if gperf preprocessing failed

12 jobs for meson-throw-error-if-cutout-python-script-custom-target-fails in 16 minutes and 16 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #6678029
meson android arm64 fedora

00:01:58

passed #6678027
gst-macos-10.15
meson macos

00:04:10

passed #6678024
meson-mingw-w64-build

00:06:07

manual #6678028
docker windows 1809 allowed to fail manual
meson msys2
passed #6678273
meson-shared-build

00:04:14

passed #6678023
meson-static-build

00:05:59

passed #6678025
docker windows 1809
meson vs2017 amd64

00:01:51

passed #6678026
docker windows 1809
meson vs2017 x86

00:01:32

passed #6678021
mingw-build

00:06:35

passed #6678019
shared-build

00:07:50

passed #6678020
static-build

00:06:34

failed #6678022
meson-shared-build

00:05:41