move stdarg header from C to cbindgen and create valist bits header

include/stdarg.h

@@ -1,10 +0,0 @@
-#ifndef _STDARG_H
-#define _STDARG_H
-
-typedef __builtin_va_list va_list;
-#define va_start(v,l)   __builtin_va_start(v,l)
-#define va_end(v)       __builtin_va_end(v)
-#define va_arg(v,l)     __builtin_va_arg(v,l)
-#define va_copy(d,s) __builtin_va_copy(d,s)
-
-#endif /* _STDARG_H */

src/header/bits_valist/cbindgen.toml

@@ -0,0 +1,18 @@
+# POSIX header spec: https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/stdarg.h.html
+#
+# This type is split out to prevent importing all of stdarg.h into other headers.
+#
+# POSIX headers that require va_list:
+# - fcntl.h (not mentioned in spec but has ... in some functions)
+# - stdarg.h (where it should be defined)
+# - stdio.h
+# - wchar.h (all of stdarg.h permitted)
+include_guard = "_RELIBC_BITS_VALIST_T_H"
+after_includes = """
+typedef __builtin_va_list va_list;
+"""
+language = "C"
+no_includes = true
+cpp_compat = true
+[enum]
+prefix_with_name = true

src/header/bits_valist/mod.rs

@@ -0,0 +1,5 @@
+//! `va_list` implementation for `stdarg.h`.
+//!
+//! See <https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/stdarg.h.html>.
+//!
+//! Implemented via typedef forwarding to the C built-in in cbindgen.

src/header/fcntl/cbindgen.toml

@@ -9,16 +9,15 @@
 # To prevent a cycle between fcntl.h and unistd.h relibc only includes fcntl.h in unistd.h.
 # This approach was chosen because unistd.h requires parts of fcntl.h but not the other way around.
 #
-# TODO split out va_list from stdarg.h
-#
-# stdarg.h brings in va_list for ...
 # sys/stat.h brings in mode_t, off_t and file mode constants
-sys_includes = ["stdarg.h", "sys/stat.h"]
+# spec does not mention va_list but some functions use ... which is effectively the same
+sys_includes = ["sys/stat.h"]
 include_guard = "_RELIBC_FCNTL_H"
 after_includes = """
-#include <bits/pid-t.h> // for pid_t from sys/types.h
-#include <bits/fcntl.h> // for SEEK_CUR, SEEK_END and SEEK_SET from stdio.h
+#include <bits/pid-t.h>      // for pid_t from sys/types.h
+#include <bits/fcntl.h>      // for SEEK_CUR, SEEK_END and SEEK_SET from stdio.h
 #include <bits/open-flags.h> // for O_* constants, shared with stdlib.h
+#include <bits/valist.h>     // for va_list from stdarg.h for ...
 """
 language = "C"
 style = "Tag"

src/header/mod.rs

@@ -62,6 +62,7 @@ pub mod bits_ucred;
 pub mod bits_uid_t;
 #[path = "bits_useconds-t/mod.rs"]
 pub mod bits_useconds_t;
+pub mod bits_valist;
 #[path = "bits_wchar-t/mod.rs"]
 pub mod bits_wchar_t;
 pub mod bits_winsize;
@@ -127,7 +128,7 @@ pub mod shadow;
 pub mod signal;
 // TODO: spawn.h
 // TODO: stdalign.h (likely C implementation)
-// stdarg.h implemented in C
+pub mod stdarg;
 // stdatomic.h implemented in C
 // stdbool.h implemented in C
 // stddef.h implemented in C

src/header/stdarg/cbindgen.toml

@@ -0,0 +1,17 @@
+# POSIX header spec: https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/stdarg.h.html
+#
+# There are no spec quotations relating to includes
+include_guard = "_RELIBC_STDARG_H"
+after_includes = """
+#include <bits/valist.h> // for va_list
+
+#define va_start(v,l)   __builtin_va_start(v,l)
+#define va_end(v)       __builtin_va_end(v)
+#define va_arg(v,l)     __builtin_va_arg(v,l)
+#define va_copy(d,s)    __builtin_va_copy(d,s)
+"""
+language = "C"
+no_includes = true
+cpp_compat = true
+[enum]
+prefix_with_name = true

src/header/stdarg/mod.rs

@@ -0,0 +1,5 @@
+//! `stdarg.h` implementation.
+//!
+//! See <https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/stdarg.h.html>.
+//!
+//! Implemented via defines forwarding to the C built-ins in cbindgen.

src/header/stdio/cbindgen.toml

@@ -8,14 +8,14 @@
 # - "The <stdio.h> header shall define NULL as described in <stddef.h>."
 # - "Inclusion of the <stdio.h> header may also make visible all symbols from <stddef.h>."
 #
-# stdarg.h brings in va_list (TODO split out)
 # stddef.h brings in size_t and NULL
 # features.h required for deprecated annotations
-sys_includes = ["stdarg.h", "stddef.h", "features.h"]
+sys_includes = ["stddef.h", "features.h"]
 after_includes = """
 #include <bits/off-t.h>   // for off_t from sys/types.h
 #include <bits/ssize-t.h> // for ssize_t from sys/types.h
 #include <bits/fcntl.h>   // for SEEK_CUR, SEEK_END and SEEK_SET
+#include <bits/valist.h>  // for va_list from stdarg.h
 """
 include_guard = "_RELIBC_STDIO_H"
 trailer = """