meson: reduce required version to 0.53

Building the libcamera Android layer currently makes use of features
from meson 0.55. The core libcamera framework in the default configuration
without android enabled uses the 'summary' feature available in 0.53, and
is the lowest supportable meson version if the Android HAL is excluded.

Ubuntu 20.04 LTS currently provides meson 0.53 and represents an
acceptable minimum version to support. Platforms utilising the Android
component will have full control over their build environment and can
ensure that they provide a more recent version of meson.

Reduce the supported meson version for the project to 0.53 to facilitate
building on more distributions without having to manually update the
meson package.

Meson will output a warning that features not available in 0.53 are used
if the Android HAL is enabled. This is considered as an acceptable
middleground to improve the experience on the latest Ubuntu LTS, until
22.04 LTS is released and provides a newer meson version.

Signed-off-by: Christian Rauch <Rauch.Christian@gmx.de>
[Kieran: Add comment about the android meson requirements]
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/README.rst b/README.rst
index 05f0e6f2..ca8a97cb 100644
--- a/README.rst
+++ b/README.rst
@@ -47,7 +47,9 @@ A C++ toolchain: [required]
         Either {g++, clang}
 
 Meson Build system: [required]
-        meson (>= 0.55) ninja-build pkg-config
+        meson (>= 0.53) ninja-build pkg-config
+
+        meson (>= 0.55) is required for building Android (-Dandroid=enabled)
 
         If your distribution doesn't provide a recent enough version of meson,
         you can install or upgrade it using pip3.