build: allow IWYU to fix includes for all .c files

Allow Include What You Use to remove unnecessary includes and only
include what is necessary. This helps with reducing compilation times
and makes it easier to visualise which dependencies are actually
required.

Work on https://github.com/neovim/neovim/issues/549, but doesn't close
it since this only works fully for .c files and not headers.

6 files changed, 46 insertions, 25 deletions

diff --git a/src/nvim/msgpack_rpc/channel.c b/src/nvim/msgpack_rpc/channel.c
index 71ed5ccf81..516af20fe9 100644
--- a/src/nvim/msgpack_rpc/channel.c
+++ b/src/nvim/msgpack_rpc/channel.c
@@ -1,36 +1,42 @@
 // This is an open source non-commercial project. Dear PVS-Studio, please check
 // it. PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
 
+#include <assert.h>
 #include <inttypes.h>
-#include <msgpack.h>
+#include <msgpack/object.h>
+#include <msgpack/pack.h>
+#include <msgpack/sbuffer.h>
+#include <msgpack/unpack.h>
 #include <stdbool.h>
-#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
 #include <uv.h>
 
 #include "klib/kvec.h"
+#include "nvim/api/private/defs.h"
+#include "nvim/api/private/dispatch.h"
 #include "nvim/api/private/helpers.h"
 #include "nvim/api/ui.h"
-#include "nvim/api/vim.h"
-#include "nvim/ascii.h"
 #include "nvim/channel.h"
-#include "nvim/eval.h"
-#include "nvim/event/libuv_process.h"
+#include "nvim/event/defs.h"
 #include "nvim/event/loop.h"
 #include "nvim/event/rstream.h"
-#include "nvim/event/socket.h"
+#include "nvim/event/stream.h"
 #include "nvim/event/wstream.h"
+#include "nvim/globals.h"
 #include "nvim/log.h"
 #include "nvim/main.h"
 #include "nvim/map.h"
 #include "nvim/memory.h"
-#include "nvim/message.h"
 #include "nvim/msgpack_rpc/channel.h"
+#include "nvim/msgpack_rpc/channel_defs.h"
 #include "nvim/msgpack_rpc/helpers.h"
 #include "nvim/msgpack_rpc/unpacker.h"
 #include "nvim/os/input.h"
-#include "nvim/os_unix.h"
+#include "nvim/rbuffer.h"
+#include "nvim/types.h"
 #include "nvim/ui.h"
-#include "nvim/vim.h"
+#include "nvim/ui_client.h"
 
 #if MIN_LOG_LEVEL > LOGLVL_DBG
 # define log_client_msg(...)
diff --git a/src/nvim/msgpack_rpc/channel.h b/src/nvim/msgpack_rpc/channel.h
index ac7911bb2c..ce5806930c 100644
--- a/src/nvim/msgpack_rpc/channel.h
+++ b/src/nvim/msgpack_rpc/channel.h
@@ -6,8 +6,10 @@
 
 #include "nvim/api/private/defs.h"
 #include "nvim/channel.h"
+#include "nvim/event/multiqueue.h"
 #include "nvim/event/process.h"
 #include "nvim/event/socket.h"
+#include "nvim/macros.h"
 #include "nvim/vim.h"
 
 #define METHOD_MAXLEN 512
diff --git a/src/nvim/msgpack_rpc/helpers.c b/src/nvim/msgpack_rpc/helpers.c
index 86babd1c36..609fef37d0 100644
--- a/src/nvim/msgpack_rpc/helpers.c
+++ b/src/nvim/msgpack_rpc/helpers.c
@@ -1,21 +1,25 @@
 // This is an open source non-commercial project. Dear PVS-Studio, please check
 // it. PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
 
-#include <inttypes.h>
-#include <msgpack.h>
+#include <msgpack/object.h>
+#include <msgpack/sbuffer.h>
+#include <msgpack/unpack.h>
+#include <msgpack/zone.h>
 #include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
 
 #include "klib/kvec.h"
-#include "nvim/api/private/dispatch.h"
+#include "msgpack/pack.h"
 #include "nvim/api/private/helpers.h"
 #include "nvim/assert.h"
-#include "nvim/log.h"
+#include "nvim/event/wstream.h"
 #include "nvim/memory.h"
 #include "nvim/msgpack_rpc/helpers.h"
-#include "nvim/vim.h"
+#include "nvim/types.h"
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
-# include "keysets.generated.h"
+# include "keysets.generated.h"  // IWYU pragma: export
 # include "msgpack_rpc/helpers.c.generated.h"
 #endif
 
diff --git a/src/nvim/msgpack_rpc/server.c b/src/nvim/msgpack_rpc/server.c
index 81b58764d7..b1e033d9f1 100644
--- a/src/nvim/msgpack_rpc/server.c
+++ b/src/nvim/msgpack_rpc/server.c
@@ -1,25 +1,22 @@
 // This is an open source non-commercial project. Dear PVS-Studio, please check
 // it. PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
 
-#include <assert.h>
 #include <inttypes.h>
-#include <stdlib.h>
+#include <stdbool.h>
+#include <stdio.h>
 #include <string.h>
+#include <uv.h>
 
-#include "nvim/ascii.h"
+#include "nvim/channel.h"
 #include "nvim/eval.h"
 #include "nvim/event/socket.h"
-#include "nvim/fileio.h"
 #include "nvim/garray.h"
 #include "nvim/log.h"
 #include "nvim/main.h"
 #include "nvim/memory.h"
-#include "nvim/msgpack_rpc/channel.h"
 #include "nvim/msgpack_rpc/server.h"
 #include "nvim/os/os.h"
-#include "nvim/path.h"
-#include "nvim/strings.h"
-#include "nvim/vim.h"
+#include "nvim/os/stdpaths_defs.h"
 
 #define MAX_CONNECTIONS 32
 #define ENV_LISTEN "NVIM_LISTEN_ADDRESS"  // deprecated
diff --git a/src/nvim/msgpack_rpc/unpacker.c b/src/nvim/msgpack_rpc/unpacker.c
index 24480835a1..e5583cf91b 100644
--- a/src/nvim/msgpack_rpc/unpacker.c
+++ b/src/nvim/msgpack_rpc/unpacker.c
@@ -1,9 +1,17 @@
 // This is an open source non-commercial project. Dear PVS-Studio, please check
 // it. PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
 
+#include <assert.h>
+#include <stdbool.h>
+#include <stdlib.h>
+
+#include "klib/kvec.h"
+#include "mpack/conv.h"
 #include "nvim/api/private/helpers.h"
-#include "nvim/log.h"
+#include "nvim/ascii.h"
+#include "nvim/macros.h"
 #include "nvim/memory.h"
+#include "nvim/msgpack_rpc/channel_defs.h"
 #include "nvim/msgpack_rpc/helpers.h"
 #include "nvim/msgpack_rpc/unpacker.h"
 #include "nvim/ui_client.h"
diff --git a/src/nvim/msgpack_rpc/unpacker.h b/src/nvim/msgpack_rpc/unpacker.h
index 35048fb877..b8b2d38d3b 100644
--- a/src/nvim/msgpack_rpc/unpacker.h
+++ b/src/nvim/msgpack_rpc/unpacker.h
@@ -7,10 +7,14 @@
 
 #include "mpack/mpack_core.h"
 #include "mpack/object.h"
+#include "nvim/api/private/defs.h"
 #include "nvim/api/private/dispatch.h"
 #include "nvim/api/private/helpers.h"
+#include "nvim/grid_defs.h"
 #include "nvim/memory.h"
 #include "nvim/msgpack_rpc/channel_defs.h"
+#include "nvim/types.h"
+#include "nvim/ui_client.h"
 
 struct Unpacker {
   mpack_parser_t parser;