protocol-cpp: fix include install dir/pkgc

protocol/meson.build

@@ -12,10 +12,10 @@ proto_generated_cpp = custom_target('protobuf-generated-sources',
     output: ['hello.pb.h', 'hello.pb.cc'],
     command: [protoc, '--proto_path=@CURRENT_SOURCE_DIR@', '--cpp_out=@OUTDIR@', '@INPUT@'],
     install: true,
-    install_dir: [get_option('includedir'), false],
+    install_dir: [get_option('includedir')+'/protocol', false],
 )
 
-lib = shared_library('protocol', proto_generated_cpp, dependencies: protobuf_dep, install: true)
+lib = shared_library('protocol', proto_generated_cpp, dependencies: [protobuf_dep], install: true)
 
 pkg = import('pkgconfig')
-pkg.generate(lib)
+pkg.generate(lib, libraries: protobuf_dep)