misc/bits/syslog.h: Clearly separate declaration from definition

This allows to include bits/syslog-decl.h in include/sys/syslog.h and
therefore be able to create the libc_hidden_builtin_proto (__syslog_chk)
prototype.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>

include/bits/syslog-decl.h

@@ -0,0 +1 @@
+#include <misc/bits/syslog-decl.h>

include/sys/syslog.h

@@ -3,6 +3,8 @@
 #include <misc/sys/syslog.h>
 #ifndef _ISOMAC
 
+#include <bits/syslog-decl.h>
+
 libc_hidden_ldbl_proto (syslog)
 
 /* __vsyslog_internal uses the same mode_flags bits as
@@ -12,5 +14,7 @@ extern void __vsyslog_internal (int pri, const char *fmt, __gnuc_va_list ap,
      attribute_hidden
      __attribute__ ((__format__ (__printf__, 2, 0)));
 
+libc_hidden_ldbl_proto (__syslog_chk)
+
 #endif /* _ISOMAC */
 #endif /* syslog.h */

misc/Makefile

@@ -64,6 +64,7 @@ headers	:= \
   sys/xattr.h \
   syslog.h \
   sys/syslog.h \
+  bits/syslog-decl.h \
   bits/syslog.h \
   bits/syslog-ldbl.h \
   bits/syslog-path.h \

misc/bits/syslog-decl.h

@@ -0,0 +1,35 @@
+/* Checking routines for syslog functions. Declaration only.
+   Copyright (C) 2023 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_SYSLOG_DECL_H
+#define _BITS_SYSLOG_DECL_H 1
+
+#ifndef _SYS_SYSLOG_H
+# error "Never include <bits/syslog-decl.h> directly; use <sys/syslog.h> instead."
+#endif
+
+extern void __syslog_chk (int __pri, int __flag, const char *__fmt, ...)
+     __attribute__ ((__format__ (__printf__, 3, 4)));
+
+#ifdef __USE_MISC
+extern void __vsyslog_chk (int __pri, int __flag, const char *__fmt,
+			   __gnuc_va_list __ap)
+     __attribute__ ((__format__ (__printf__, 3, 0)));
+#endif
+
+#endif

misc/bits/syslog.h

@@ -20,15 +20,7 @@
 # error "Never include <bits/syslog.h> directly; use <sys/syslog.h> instead."
 #endif
 
-
-extern void __syslog_chk (int __pri, int __flag, const char *__fmt, ...)
-     __attribute__ ((__format__ (__printf__, 3, 4)));
-
-#ifdef __USE_MISC
-extern void __vsyslog_chk (int __pri, int __flag, const char *__fmt,
-			   __gnuc_va_list __ap)
-     __attribute__ ((__format__ (__printf__, 3, 0)));
-#endif
+#include <bits/syslog-decl.h>
 
 #include <bits/floatn.h>
 #if defined __LDBL_COMPAT || __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 1

misc/syslog.c

@@ -101,7 +101,7 @@ __vsyslog (int pri, const char *fmt, va_list ap)
 ldbl_weak_alias (__vsyslog, vsyslog)
 
 void
-__syslog_chk (int pri, int flag, const char *fmt, ...)
+___syslog_chk (int pri, int flag, const char *fmt, ...)
 {
   va_list ap;
 
@@ -109,6 +109,8 @@ __syslog_chk (int pri, int flag, const char *fmt, ...)
   __vsyslog_internal (pri, fmt, ap, (flag > 0) ? PRINTF_FORTIFY : 0);
   va_end (ap);
 }
+ldbl_hidden_def (___syslog_chk, __syslog_chk)
+ldbl_strong_alias (___syslog_chk, __syslog_chk)
 
 void
 __vsyslog_chk (int pri, int flag, const char *fmt, va_list ap)

sysdeps/ieee754/ldbl-128ibm-compat/ieee128-syslog.c

@@ -52,6 +52,7 @@ ___ieee128___syslog_chk (int pri, int flag, const char *fmt, ...)
   __vsyslog_internal (pri, fmt, ap, mode);
   va_end (ap);
 }
+hidden_def (___ieee128___syslog_chk)
 strong_alias (___ieee128___syslog_chk, __syslog_chkieee128)
 
 void