libs: Add static compatiblity check for Rust

This patch adds a static compatiblity check
for most of structures from NuttX, which is used by Rust.

Currently, for most of them have a reserved field, which is for possible future use,
you can refer to https://github.com/no1wudi/libc/blob/39277b5357cb2aa7af1bd8344956ec292c35abed/src/unix/nuttx/mod.rs#L71
for more details.

I think we should define the initial version carefully, to avoid compatiblity problems in future as much as possible:
1. Struct reserved size is 2 pointer size, is it sufficient?
2. Which option should we preferred to use? Such as SYSTEM_TIME64 and FS_LARGEFILE?
3. Should we enable it by default to cover more cases in build CI? It can prevent introduce compatiblity issues.

Signed-off-by: Huang Qi <[email protected]>

libs/libc/Kconfig

@@ -34,3 +34,4 @@ source "libs/libc/regex/Kconfig"
 source "libs/libc/gnssutils/Kconfig"
 source "libs/libc/fdt/Kconfig"
 source "libs/libc/queue/Kconfig"
+source "libs/libc/librust/Kconfig"

libs/libc/Makefile

@@ -70,6 +70,7 @@ include wchar/Make.defs
 include wctype/Make.defs
 include wqueue/Make.defs
 include fdt/Make.defs
+include librust/Make.defs
 
 # Use double delim to fix windows native build and give an error:
 # makefile:132: *** target mode do not include“%”. stop.

libs/libc/librust/CMakeLists.txt

@@ -0,0 +1,23 @@
+# ##############################################################################
+# libs/librust/CMakeLists.txt
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more contributor
+# license agreements.  See the NOTICE file distributed with this work for
+# additional information regarding copyright ownership.  The ASF licenses this
+# file to you under the Apache License, Version 2.0 (the "License"); you may not
+# use this file except in compliance with the License.  You may obtain a copy of
+# the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+# License for the specific language governing permissions and limitations under
+# the License.
+#
+# ##############################################################################
+
+if(CONFIG_LIBRUST)
+  target_sources(c PRIVATE lib_rust.c)
+endif()

libs/libc/librust/Kconfig

@@ -0,0 +1,16 @@
+#
+# For a description of the syntax of this configuration file,
+# see the file kconfig-language.txt in the NuttX tools repository.
+#
+
+config LIBRUST
+	bool "Rust Runtime Compatibility Static Checker"
+	default y
+	depends on SYSTEM_TIME64
+	depends on FS_LARGEFILE
+	depends on !SMALL_MEMORY
+	depends on TLS_NELEM > 0
+	---help---
+		This option enables building and linking with Rust language support.
+		Currently, it only do static checking for the compatibility of structs
+		between Rust and C side.

libs/libc/librust/Make.defs

@@ -0,0 +1,30 @@
+############################################################################
+# libs/libc/librust/Make.defs
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.  The
+# ASF licenses this file to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance with the
+# License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+# License for the specific language governing permissions and limitations
+# under the License.
+#
+############################################################################
+
+ifeq ($(CONFIG_LIBRUST),y)
+# Add the librust C files to the build
+
+CSRCS += lib_rust.c
+
+# Add the librust directory to the build
+
+DEPPATH += --dep-path librust
+VPATH += :librust
+endif