feature_test_macros.7: Remove mention of bogus _ISOC95_SOURCE macro

The _ISOC95_SOURCE macro is defined in <features.h>, but it
does nothing. So remove discussion of it, and move some of
the discussion of C95 under the ISOC99_SOURCE subhead.

Reported-by: Joseph S. Myers <joseph@codesourcery.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
feature_test_macros.7: Reword description of C90

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
feature_test_macros.7: Add packaging note for _BSD_SOURCE/_SVID_SOURCE/_DEFAULT_SOURCE

To compile warning-free across glibc < 2.20 and glibc >= 2.20
code may been to define both _DEFAULT_SOURCE and either
_BSD_SOURCE or _SVID_SOURCE.

Reported-by: Carlos O'Donell <carlos@redhat.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
core.5: Document %P core_pattern specifier

Reported-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
core.5: Tweaks to Mike Frysinger's %P patch

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
core.5: Document core_pattern %d specifier

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
core.5: Tweaks to Mike Frysinger's %d patch

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
core.5: Rearrange core_pattern specifiers alphabetically

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
readahead.2: Don't claim the call blocks until all data has been read

The readahead(2) man page was claiming that the call blocks until
all data has been read into the cache.  This is incorrect.

See https://bugzilla.kernel.org/show_bug.cgi?id=54271

Corrado Zoccolo noted:
        it simply calls force_page_cache_readahead (the same called
        by fadvise/madvise), that just post a prefetch, and it may
        block only when the I/O queue is full.

Reported-by: Corrado Zoccolo <czoccolo@gmail.com>
Reported-by: Gregory P. Smith <gps@google.com>
Reported-by: Zhu Yanhai <zhu.yanhai@gmail.com>
Signed-off-by: Phillip Susi <psusi@ubuntu.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
readahead.2: Tweaks to Phillip Susi;s patch

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
readahead.2: Place note about blocking behavior of readahead() under BUGS

Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
readahead.2: tfix

Reported-by: Phillip Susi <psusi@ubuntu.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
proc.5: tfix

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
man-pages.7: Add preferred term "superblock"

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
readahead.2: spfix

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
shmget.2: spfix

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
perfmonctl.2: spfix

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
poll.2: spfix

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
select.2: spfix

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
fcntl.2: spfix

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