poll.2, atoi.3, gsignal.3, posix_memalign.3, scanf.3: Remove a few mentions of the ancient "Linux libc"

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

man2/poll.2

@@ -387,8 +387,7 @@ The
 .BR poll ()
 system call was introduced in Linux 2.1.23.
 On older kernels that lack this system call,
-.\" library call was introduced in libc 5.4.28
-the glibc (and the old Linux libc)
+the glibc
 .BR poll ()
 wrapper function provides emulation using
 .BR select (2).

man3/atoi.3

@@ -104,13 +104,13 @@ POSIX.1-1996 include the functions
 and
 .BR atol ()
 only.
-.SH NOTES
-Linux libc provided
-.BR atoq ()
-as an obsolete name for
-.BR atoll ();
-.BR atoq ()
-is not provided by glibc.
+.\" .SH NOTES
+.\" Linux libc provided
+.\" .BR atoq ()
+.\" as an obsolete name for
+.\" .BR atoll ();
+.\" .BR atoq ()
+.\" is not provided by glibc.
 .\" The
 .\" .BR atoll ()
 .\" function is present in glibc 2 since version 2.0.2, but

man3/gsignal.3

@@ -114,7 +114,9 @@ T}	Thread safety	MT-Safe sigintr
 .SH CONFORMING TO
 These functions are available under AIX, DG/UX, HP-UX, SCO, Solaris, Tru64.
 They are called obsolete under most of these systems, and are
-broken under Linux libc and glibc.
+broken under
+.\" Linux libc and
+glibc.
 Some systems also have
 .BR gsignal_r ()
 and

man3/posix_memalign.3

@@ -177,7 +177,7 @@ The functions
 .BR valloc (),
 and
 .BR pvalloc ()
-have been available in all Linux libc libraries.
+have been available since at least glibc 2.0.
 .PP
 The function
 .BR aligned_alloc ()

man3/scanf.3

@@ -395,15 +395,15 @@ and assignment does not occur.
 Matches an optionally signed decimal integer;
 the next pointer must be a pointer to
 .IR int .
-.TP
-.B D
-Equivalent to
-.IR ld ;
-this exists only for backward compatibility.
-(Note: thus only in libc4.
-In libc5 and glibc the
-.B %D
-is silently ignored, causing old programs to fail mysteriously.)
+.\" .TP
+.\" .B D
+.\" Equivalent to
+.\" .IR ld ;
+.\" this exists only for backward compatibility.
+.\" (Note: thus only in libc4
+.\" In libc5 and glibc the
+.\" .B %D
+.\" is silently ignored, causing old programs to fail mysteriously.)
 .TP
 .B i
 Matches an optionally signed integer; the next pointer must be a pointer to