meson: Replace obselete join_paths() with '/' operator

Since meson v0.49.0, join_paths() is equivalent to '/' hence,
drop and replace it with '/' short-hand in meson files.

This commit does not introduce any functional changes.

Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

src/libcamera/meson.build

@@ -103,7 +103,7 @@ endforeach
 
 libcamera_sources += control_sources
 
-gen_version = join_paths(meson.source_root(), 'utils', 'gen-version.sh')
+gen_version = meson.source_root() / 'utils' / 'gen-version.sh'
 
 version_cpp = vcs_tag(command : [gen_version, meson.build_root()],
                       input : 'version.cpp.in',

src/libcamera/proxy/worker/meson.build

@@ -1,6 +1,6 @@
 # SPDX-License-Identifier: CC0-1.0
 
-proxy_install_dir = join_paths(get_option('libexecdir'), 'libcamera')
+proxy_install_dir = get_option('libexecdir') / 'libcamera'
 
 # generate {pipeline}_ipa_proxy_worker.cpp
 foreach mojom : ipa_mojoms
@@ -25,4 +25,4 @@ foreach mojom : ipa_mojoms
 endforeach
 
 config_h.set('IPA_PROXY_DIR',
-             '"' + join_paths(get_option('prefix'), proxy_install_dir) + '"')
+             '"' + get_option('prefix') / proxy_install_dir + '"')