Various pages: Normalize SYNOPSIS notes about nonexistent glibc wrappers

To easily distinguish documentation about glibc wrappers from
documentation about kernel syscalls, let's have a normalized
'Note' in the SYNOPSIS, and a further explanation in the page body
(NOTES in most of them), as already happened in many (but not all)
of the manual pages for syscalls without a wrapper.  Furthermore,
let's normalize the messages, following membarrier.2 (because it's
already quite extended), so that it's easy to use grep to find
those pages.

To find these pages, we used:
$ grep -rn wrapper man? | sort -V
and
$ grep -rni support.*glibc | sort -V

delete_module.2, init_module.2:  glibc 2.23 is no longer
  maintained, so we changed the notes about wrappers, to say that
  there are no glibc wrappers for these system calls; see NOTES.

We didn't fix some obsolete pages such as create_module.2.

Signed-off-by: Ganimedes Colomar <gacoan.linux@gmail.com>
Cowritten-by: Alejandro Colomar <alx.manpages@gmail.com>
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

man2/add_key.2

@@ -22,7 +22,8 @@ add_key \- add a key to the kernel's key management facility
 .BI "                     key_serial_t " keyring ");"
 .fi
 .PP
-No glibc wrapper is provided for this system call; see NOTES.
+.IR Note :
+There is no glibc wrapper for this system call; see NOTES.
 .SH DESCRIPTION
 .BR add_key ()
 creates or updates a key of the given

man2/arch_prctl.2

@@ -33,6 +33,9 @@ arch_prctl \- set architecture-specific thread state
 .BI "int arch_prctl(int " code ", unsigned long " addr );
 .BI "int arch_prctl(int " code ", unsigned long *" addr );
 .fi
+.PP
+.IR Note :
+There is no glibc wrapper for this system call; see NOTES.
 .SH DESCRIPTION
 .BR arch_prctl ()
 sets architecture-specific process or thread state.

man2/clone.2

@@ -60,7 +60,7 @@ clone, __clone2, clone3 \- create a child process
 .fi
 .PP
 .IR Note :
-There is not yet a glibc wrapper for
+There is no glibc wrapper for
 .BR clone3 ();
 see NOTES.
 .SH DESCRIPTION

man2/delete_module.2

@@ -31,7 +31,7 @@ delete_module \- unload a kernel module
 .fi
 .PP
 .IR Note :
-No declaration of this system call is provided in glibc headers; see NOTES.
+There is no glibc wrapper for this system call; see NOTES.
 .SH DESCRIPTION
 The
 .BR delete_module ()

man2/init_module.2

@@ -37,11 +37,7 @@ init_module, finit_module \- load a kernel module
 .fi
 .PP
 .IR Note :
-glibc provides no header file declaration of
-.BR init_module ()
-and no wrapper function for
-.BR finit_module ();
-see NOTES.
+There are no glibc wrappers for these system calls; see NOTES.
 .SH DESCRIPTION
 .BR init_module ()
 loads an ELF image into kernel space,

man2/keyctl.2

@@ -45,7 +45,8 @@ keyctl \- manipulate the kernel's key management facility
 .BI "             __kernel_ulong_t " arg5 );
 .fi
 .PP
-No glibc wrapper is provided for this system call; see NOTES.
+.IR Note :
+There is no glibc wrapper for this system call; see NOTES.
 .SH DESCRIPTION
 .BR keyctl ()
 allows user-space programs to perform key manipulation.

man2/pidfd_getfd.2

@@ -29,6 +29,9 @@ pidfd_getfd \- obtain a duplicate of another process's file descriptor
 .nf
 .BI "int pidfd_getfd(int " pidfd ", int " targetfd ", unsigned int " flags );
 .fi
+.PP
+.IR Note :
+There is no glibc wrapper for this system call; see NOTES.
 .SH DESCRIPTION
 The
 .BR pidfd_getfd ()

man2/pidfd_open.2

@@ -31,6 +31,9 @@ pidfd_open \- obtain a file descriptor that refers to a process
 .PP
 .BI "int pidfd_open(pid_t " pid ", unsigned int " flags );
 .fi
+.PP
+.IR Note :
+There is no glibc wrapper for this system call; see NOTES.
 .SH DESCRIPTION
 The
 .BR pidfd_open ()

man2/pidfd_send_signal.2

@@ -32,6 +32,8 @@ pidfd_send_signal \- send a signal to a process specified by a file descriptor
 .BI "int pidfd_send_signal(int " pidfd ", int " sig ", siginfo_t *" info ,
 .BI "                      unsigned int " flags );
 .fi
+.IR Note :
+There is no glibc wrapper for this system call; see NOTES.
 .SH DESCRIPTION
 The
 .BR pidfd_send_signal ()

man2/request_key.2

@@ -22,7 +22,8 @@ request_key \- request a key from the kernel's key management facility
 .BI "                         key_serial_t " dest_keyring ");"
 .fi
 .PP
-No glibc wrapper is provided for this system call; see NOTES.
+.IR Note :
+There is no glibc wrapper for this system call; see NOTES.
 .SH DESCRIPTION
 .BR request_key ()
 attempts to find a key of the given

man2/s390_guarded_storage.2

@@ -31,6 +31,9 @@ s390_guarded_storage \- operations with z/Architecture guarded storage facility
 .PP
 .BI "int s390_guarded_storage(int " command ", struct gs_cb *" gs_cb ");"
 .fi
+.PP
+.IR Note :
+There is no glibc wrapper for this system call; see NOTES.
 .SH DESCRIPTION
 The
 .BR s390_guarded_storage ()

man2/s390_pci_mmio_write.2

@@ -35,6 +35,9 @@ MMIO memory page
 .BI "int s390_pci_mmio_read(unsigned long " mmio_addr ","
 .BI "                        void *" user_buffer ", size_t " length ");"
 .fi
+.PP
+.IR Note :
+There are no glibc wrappers for these system calls; see NOTES.
 .SH DESCRIPTION
 The
 .BR s390_pci_mmio_write ()

man2/s390_runtime_instr.2

@@ -31,6 +31,9 @@ s390_runtime_instr \- enable/disable s390 CPU run-time instrumentation
 .PP
 .BI "int s390_runtime_instr(int " command ", int " signum ");"
 .fi
+.PP
+.IR Note :
+There is no glibc wrapper for this system call; see NOTES.
 .SH DESCRIPTION
 The
 .BR s390_runtime_instr ()

man2/s390_sthyi.2

@@ -32,6 +32,9 @@ s390_sthyi \- emulate STHYI instruction
 .BI "int s390_sthyi(unsigned long " function_code ", void *" resp_buffer ","
 .BI "               uint64_t *" return_code ", unsigned long " flags ");"
 .fi
+.PP
+.IR Note :
+There is no glibc wrapper for this system call; see NOTES.
 .SH DESCRIPTION
 The
 .BR s390_sthyi ()

man2/seccomp.2

@@ -41,6 +41,9 @@ seccomp \- operate on Secure Computing state of the process
 .BI "int seccomp(unsigned int " operation ", unsigned int " flags \
 ", void *" args );
 .fi
+.PP
+.IR Note :
+There is no glibc wrapper for this system call; see NOTES.
 .SH DESCRIPTION
 The
 .BR seccomp ()

man2/syslog.2

@@ -36,7 +36,6 @@ set console_loglevel
 .SH SYNOPSIS
 .nf
 .BI "int syslog(int " type ", char *" bufp ", int " len );
-.B  "                /* No wrapper provided in glibc */"
 .PP
 /* The glibc interface */
 .B "#include <sys/klog.h>"