GH-45772: [C++] Export Arrow as dependency from Meson configuration

Author: WillAyd

cpp/src/arrow/meson.build

@@ -326,6 +326,11 @@ arrow_lib = library(
     install: true,
 )
 
+arrow_dep = declare_dependency(
+    include_directores: [include_dir],
+    link_with: arrow_lib,
+)
+
 # Meson does not allow you to glob for headers to install. See also
 # https://mesonbuild.com/FAQ.html#why-cant-i-specify-target-files-with-a-wildcard
 # install_subdir would be usable if the directory only contained headers