meson: fix installing the includes

12 jobs for master in 4 minutes and 38 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #242745
amd64 debian
build-debian

00:00:33

passed #242749
debian aarch64
build-debian-aarch64

00:01:31

passed #242750
debian aarch64
build-debian-aarch64-clang-5

00:01:06

passed #242746
amd64 debian
build-debian-static

00:00:32

passed #242752
debian aarch64
build-debian-werror

00:00:29

passed #242751
macos
build-macos

00:00:28

passed #242747
win32
build-win32

00:00:29

passed #242748
win64
build-win64

00:00:36

 
  Test
passed #242753
amd64 debian
test-debian

00:00:44

passed #242754
amd64 debian
test-debian-asan

00:02:09

passed #242755
amd64 debian
test-debian-msan

00:00:57

passed #242756
amd64 debian
test-debian-ubsan

00:01:18