doc: document namespace pollution allowed by POSIX

In the manual, document where POSIX.1-2024 allows namespace pollution.
Although it might be nice to add something like GNULIB_POSIXCHECK to
detect when Gnulib-using code is unportable in this area, I don’t
offhand see a good way to do that.

doc/posix-headers/arpa_inet.texi

@@ -14,4 +14,10 @@ This header file is missing on some platforms: mingw, MSVC 14.
 
 Portability problems not fixed by Gnulib:
 @itemize
+@item
+POSIX.1-2024 allows, but does not require, this file to make visible
+all symbols from the headers @code{<inttypes.h>} and @code{<netinet/in.h>}.
+Programs should not assume that these other symbols are visible merely
+because this file is included, or that they are invisible because only
+this file is included.
 @end itemize

doc/posix-headers/endian.texi

@@ -19,4 +19,10 @@ macOS 14, FreeBSD 13.0, NetBSD 7.1, OpenBSD 3.8, Minix 3.1.8, AIX 7.3.1, HP-UX 1
 
 Portability problems not fixed by Gnulib:
 @itemize
+@item
+POSIX.1-2024 allows, but does not require, this file to make visible
+all symbols from the header @code{<stdint.h>}.
+Programs should not assume that these other symbols are visible merely
+because this file is included, or that they are invisible because only
+this file is included.
 @end itemize

doc/posix-headers/fcntl.texi

@@ -157,4 +157,11 @@ functions like @samp{openat}.
 Instead, you can use @samp{AT_FDCWD == -1 ? -2 : -1}.
 @samp{AT_FDCWD} is @minus{}1 on some platforms:
 Haiku R1/Beta4.
+
+@item
+POSIX.1-2024 allows, but does not require, this file to make visible
+all symbols from the headers @code{<sys/stat.h>} and @code{<unistd.h>}.
+Programs should not assume that these other symbols are visible merely
+because this file is included, or that they are invisible because only
+this file is included.
 @end itemize

doc/posix-headers/ftw.texi

@@ -14,4 +14,11 @@ Portability problems not fixed by Gnulib:
 @item
 This header file is missing on some platforms:
 FreeBSD 5.2.1, NetBSD 3.0, Minix 3.1.8, mingw, MSVC 14.
+
+@item
+POSIX.1-2024 allows, but does not require, this file to make visible
+all symbols from the header @code{<sys/stat.h>}.
+Programs should not assume that these other symbols are visible merely
+because this file is included, or that they are invisible because only
+this file is included.
 @end itemize

doc/posix-headers/langinfo.texi

@@ -30,4 +30,10 @@ OpenBSD 7.5.
 
 Portability problems not fixed by Gnulib:
 @itemize
+@item
+POSIX.1-2024 allows, but does not require, this file to make visible
+all symbols from the header @code{<nl_types.h>}.
+Programs should not assume that these other symbols are visible merely
+because this file is included, or that they are invisible because only
+this file is included.
 @end itemize

doc/posix-headers/netdb.texi

@@ -41,4 +41,11 @@ musl libc 1.2.4, OpenBSD 7.5.
 
 Portability problems not fixed by Gnulib:
 @itemize
+@item
+POSIX.1-2024 allows, but does not require, this file to make visible
+all symbols from the headers @code{<inttypes.h>},
+@code{<netnet/in.h>}, and @code{<sys/socket.h>}.
+Programs should not assume that these other symbols are visible merely
+because this file is included, or that they are invisible because only
+this file is included.
 @end itemize

doc/posix-headers/netinet_in.texi

@@ -19,4 +19,11 @@ OpenBSD 4.6.
 
 Portability problems not fixed by Gnulib:
 @itemize
+@item
+POSIX.1-2024 allows, but does not require, this file to make visible
+all symbols from the headers @code{<arpa/inet.h>}, @code{<inttypes.h>}
+and @code{<sys/socket.h>}.
+Programs should not assume that these other symbols are visible merely
+because this file is included, or that they are invisible because only
+this file is included.
 @end itemize

doc/posix-headers/poll.texi

@@ -15,4 +15,10 @@ mingw, MSVC 14.
 
 Portability problems not fixed by Gnulib:
 @itemize
+@item
+POSIX.1-2024 allows, but does not require, this file to make visible
+all symbols from the headers @code{<signal.h>} and @code{<time.h>}.
+Programs should not assume that these other symbols are visible merely
+because this file is included, or that they are invisible because only
+this file is included.
 @end itemize

doc/posix-headers/sched.texi

@@ -25,4 +25,10 @@ Haiku.
 
 Portability problems not fixed by Gnulib:
 @itemize
+@item
+POSIX.1-2024 allows, but does not require, this file to make visible
+all symbols from the header @code{<time.h>}.
+Programs should not assume that these other symbols are visible merely
+because this file is included, or that they are invisible because only
+this file is included.
 @end itemize

doc/posix-headers/signal.texi

@@ -47,4 +47,11 @@ mingw, MSVC 14.
 The macro @code{SIGBUS} is set to the same value as @code{SIGSEGV},
 rather than being a distinct signal, on some platforms:
 Haiku.
+
+@item
+POSIX.1-2024 allows, but does not require, this file to make visible
+all symbols from the header @code{<time.h>}.
+Programs should not assume that these other symbols are visible merely
+because this file is included, or that they are invisible because only
+this file is included.
 @end itemize

doc/posix-headers/stdio.texi

@@ -28,4 +28,10 @@ NetBSD 5.0
 
 Portability problems not fixed by Gnulib:
 @itemize
+@item
+POSIX.1-2024 allows, but does not require, this file to make visible
+all symbols from the header @code{<stddef.h>}.
+Programs should not assume that these other symbols are visible merely
+because this file is included, or that they are invisible because only
+this file is included.
 @end itemize

doc/posix-headers/stdlib.texi

@@ -53,4 +53,12 @@ To get them, import Gnulib module @code{call_once} and include
 System status macros such as @code{WEXITSTATUS} require an lvalue
 argument on some platforms.
 macOS 11.1.
+
+@item
+POSIX.1-2024 allows, but does not require, this file to make visible
+all symbols from the headers @code{<fcntl.h>}, @code{<limits.h>},
+@code{<math.h>}, @code{<stddef.h>}, and @code{<sys/wait.h>}.
+Programs should not assume that these other symbols are visible merely
+because this file is included, or that they are invisible because only
+this file is included.
 @end itemize

doc/posix-headers/string.texi

@@ -16,4 +16,10 @@ NetBSD 5.0
 
 Portability problems not fixed by Gnulib:
 @itemize
+@item
+POSIX.1-2024 allows, but does not require, this file to make visible
+all symbols from the header @code{<stddef.h>}.
+Programs should not assume that these other symbols are visible merely
+because this file is included, or that they are invisible because only
+this file is included.
 @end itemize

doc/posix-headers/sys_mman.texi

@@ -14,4 +14,11 @@ Portability problems not fixed by Gnulib:
 @item
 This header file is missing on some platforms:
 mingw, MSVC 14.
+
+@item
+POSIX.1-2024 allows, but does not require, this file to make visible
+all symbols from the header @code{<fcntl.h>}.
+Programs should not assume that these other symbols are visible merely
+because this file is included, or that they are invisible because only
+this file is included.
 @end itemize

doc/posix-headers/sys_resource.texi

@@ -27,4 +27,11 @@ Portability problems not fixed by Gnulib:
 On some platforms, this header does not define some or all of the
 symbolic constants required by POSIX@.  For example, OpenVMS and Android do
 not define @code{RLIM_SAVED_CUR} or @code{RLIM_SAVED_MAX}.
+
+@item
+POSIX.1-2024 allows, but does not require, this file to make visible
+all symbols from the header @code{<sys/time.h>}.
+Programs should not assume that these other symbols are visible merely
+because this file is included, or that they are invisible because only
+this file is included.
 @end itemize

doc/posix-headers/sys_select.texi

@@ -22,4 +22,10 @@ AIX 7.1, Solaris 11.4.
 
 Portability problems not fixed by Gnulib:
 @itemize
+@item
+POSIX.1-2024 allows, but does not require, this file to make visible
+all symbols from the headers @code{<signal.h>} and @code{<time.h>}.
+Programs should not assume that these other symbols are visible merely
+because this file is included, or that they are invisible because only
+this file is included.
 @end itemize

doc/posix-headers/sys_socket.texi

@@ -91,4 +91,10 @@ glibc 2.42, musl libc, macOS, FreeBSD, NetBSD, OpenBSD, AIX, Solaris 11.3, Cygwi
 This header file does not define the constant @code{MSG_CMSG_CLOFORK}
 on some platforms:
 glibc 2.42, musl libc, macOS, FreeBSD, NetBSD, OpenBSD, AIX, Solaris 11.4, Cygwin, mingw, MSVC, Android.
+@item
+POSIX.1-2024 allows, but does not require, this file to make visible
+all symbols from the header @code{<sys/uio.h>}.
+Programs should not assume that these other symbols are visible merely
+because this file is included, or that they are invisible because only
+this file is included.
 @end itemize

doc/posix-headers/sys_stat.texi

@@ -90,6 +90,12 @@ symlinks;
 @mindex areadlink-with-size
 use the Gnulib module @code{areadlink-with-size} for a
 better way to get symlink contents.
+@item
+POSIX.1-2024 allows, but does not require, this file to make visible
+all symbols from the header @code{<time.h>}.
+Programs should not assume that these other symbols are visible merely
+because this file is included, or that they are invisible because only
+this file is included.
 @end itemize
 
 @mindex same-inode

doc/posix-headers/sys_time.texi

@@ -32,4 +32,11 @@ Portability problems not fixed by Gnulib:
 @samp{struct timeval} is defined with a @code{tv_sec} type that is
 wider than @code{time_t}:
 OpenBSD 5.1 in 64-bit mode.
+
+@item
+POSIX.1-2024 allows, but does not require, this file to make visible
+all symbols from the header @code{<sys/select.h>}.
+Programs should not assume that these other symbols are visible merely
+because this file is included, or that they are invisible because only
+this file is included.
 @end itemize

doc/posix-headers/sys_wait.texi

@@ -22,4 +22,11 @@ Portability problems not fixed by Gnulib:
 System status macros such as @code{WEXITSTATUS} require an lvalue
 argument on some platforms:
 macOS 11.1.
+
+@item
+POSIX.1-2024 allows, but does not require, this file to make visible
+all symbols from the header @code{<signal.h>}.
+Programs should not assume that these other symbols are visible merely
+because this file is included, or that they are invisible because only
+this file is included.
 @end itemize

doc/posix-headers/time.texi

@@ -63,4 +63,11 @@ rolls around, which will occur in 2038 for the typical case when
 On some platforms the @code{tv_nsec} member of @code{struct timespec}
 is not of type @code{long}, but is of type @code{long long} instead:
 glibc x32
+
+@item
+POSIX.1-2024 allows, but does not require, this file to make visible
+all symbols from the header @code{<signal.h>}.
+Programs should not assume that these other symbols are visible merely
+because this file is included, or that they are invisible because only
+this file is included.
 @end itemize

doc/posix-headers/uchar.texi

@@ -37,4 +37,11 @@ implementations.
 
 Portability problems not fixed by Gnulib:
 @itemize
+@item
+POSIX.1-2024 allows, but does not require, this file to make visible
+all symbols from the headers @code{<stddef.h>}, @code{<stdint.h>}, and
+@code{<wchar.h>}.
+Programs should not assume that these other symbols are visible merely
+because this file is included, or that they are invisible because only
+this file is included.
 @end itemize

doc/posix-headers/unistd.texi

@@ -35,4 +35,11 @@ NetBSD 5.0
 
 Portability problems not fixed by Gnulib:
 @itemize
+@item
+POSIX.1-2024 allows, but does not require, this file to make visible
+all symbols from the headers @code{<fcntl.h>}, @code{<stddef.h>},
+@code{<stdint.h>}, and @code{<stdio.h>}.
+Programs should not assume that these other symbols are visible merely
+because this file is included, or that they are invisible because only
+this file is included.
 @end itemize

doc/posix-headers/utmpx.texi

@@ -54,4 +54,10 @@ The @code{readutmp} module works around this problem:
 glibc 2.38 on 32-bit platforms like x86 and ARM where @code{time_t}
 was historically 32 bits.
 @xref{Avoiding the year 2038 problem}.
+@item
+POSIX.1-2024 allows, but does not require, this file to make visible
+all symbols from the header @code{<sys/time.h>}.
+Programs should not assume that these other symbols are visible merely
+because this file is included, or that they are invisible because only
+this file is included.
 @end itemize

doc/posix-headers/wchar.texi

@@ -28,4 +28,12 @@ This header file leads to link errors and endless recursions or endless loops
 on some platforms:
 glibc version 2.5 or older, together with gcc version 4.3 or newer and the
 option @samp{-std=c99} or @samp{-std=gnu99}.
+@item
+POSIX.1-2024 allows, but does not require, this file to make visible
+all symbols from the headers @code{<ctype.h>}, @code{<stdarg.h>},
+@code{<stddef.h>}, @code{<stdlib.h>}, @code{<stdio.h>},
+@code{<string.h>}, and @code{<time.h>}.
+Programs should not assume that these other symbols are visible merely
+because this file is included, or that they are invisible because only
+this file is included.
 @end itemize

doc/posix-headers/wctype.texi

@@ -21,4 +21,12 @@ FreeBSD 4.11.
 
 Portability problems not fixed by Gnulib:
 @itemize
+@item
+POSIX.1-2024 allows, but does not require, this file to make visible
+all symbols from the headers @code{<ctype.h>}, @code{<stdarg.h>},
+@code{<stddef.h>}, @code{<stdlib.h>}, @code{<stdio.h>},
+@code{<string.h>}, @code{<time.h>}, and @code{<wchar.h>}.
+Programs should not assume that these other symbols are visible merely
+because this file is included, or that they are invisible because only
+this file is included.
 @end itemize