@cvindex HAVE_STRFTIME
@c @fuindex strftime
@prindex @code{strftime}
-Check for @code{strftime} in the @file{intl} library, for SCO Unix.
+Check for @code{strftime} in the @file{intl} library.
Then, if @code{strftime} is available, define @code{HAVE_STRFTIME}.
This macro is obsolescent, as no current systems require the @file{intl}
the length of a directory entry name by passing a pointer to a
@code{struct dirent} to the @code{NAMLEN} macro.
-This macro also checks for the SCO Xenix @file{dir} and @file{x} libraries.
+This macro also checks for the obsolete @file{dir} and @file{x} libraries.
This macro is obsolescent, as all current systems with directory
libraries have @code{<dirent.h>}. New programs need not use this macro.
@caindex prog_cxx_openmp
@caindex prog_f77_openmp
@caindex prog_fc_openmp
-@uref{http://@/www.openmp.org/, OpenMP} specifies extensions of C, C++,
+@uref{https://@/www.openmp.org/, OpenMP} specifies extensions of C, C++,
and Fortran that simplify optimization of shared memory parallelism,
which is a common problem on multi-core CPUs.
@code{AC_CONFIG_HEADERS}, be sure that @file{config.h} is included
before any system header.
-The following preprocessor macros are defined unconditionally:
+Define the following preprocessor macros unconditionally:
@table @code
@item _ALL_SOURCE
@cvindex _ALL_SOURCE
-Enable extensions on AIX 3 and Interix.
+Enable extensions on AIX and z/OS.
@item _DARWIN_C_SOURCE
@cvindex _DARWIN_C_SOURCE
Enable extensions on macOS.
@item _XOPEN_SOURCE
@cvindex _XOPEN_SOURCE
Defined (with value 500) only if needed to make @file{wchar.h} declare
-@code{mbstate_t}. This is known to be necessary on some versions of HP/UX.
+@code{mbstate_t}. This is known to be necessary on some versions of HP-UX.
@end table
@cvindex __STDC_WANT_DEC_FP__
@cvindex __STDC_WANT_LIB_EXT1__
The C preprocessor macro @code{__STDC_WANT_LIB_EXT1__} is not defined,
as the C standard's Annex K is problematic. See: O'Donell C, Sebor M.
-@uref{http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1967.htm, Field
+@uref{https://www.open-std.org/jtc1/sc22/wg14/www/docs/n1967.htm, Field
Experience With Annex K---Bounds Checking Interfaces}.
The Autoconf macro @code{AC_USE_SYSTEM_EXTENSIONS} was introduced in
systems} are derived from the
@uref{https://@/en.wikipedia.org/@/wiki/@/Unix, Unix operating system}.
-The @uref{http://@/bhami.com/@/rosetta.html, Rosetta Stone for Unix}
+The @uref{https://@/bhami.com/@/rosetta.html, Rosetta Stone for Unix}
contains a table correlating the features of various Posix-conforming
systems. @uref{https://@/www.levenez.com/@/unix/, Unix History} is a
simplified diagram of how many Unix systems were derived from each
other.
-@uref{http://@/heirloom.sourceforge.net/, The Heirloom Project}
+@uref{https://@/heirloom.sourceforge.net/, The Heirloom Project}
provides some variants of traditional implementations of Unix utilities.
@table @asis
@file{configure} scripts and M4sh do that for you.
Export these variables after setting them.
-@c However, some older, nonstandard
-@c systems (notably SCO) break if locale environment variables
-@c are set to @samp{C}, so when running on these systems
-@c Autoconf-generated scripts unset the variables instead.
-
@item LANGUAGE
@evindex LANGUAGE
Almost all modern systems use IEEE-754 floating point, and it is safe to
assume IEEE-754 in most portable code these days. For more information,
please see David Goldberg's classic paper
-@uref{http://@/www.validlab.com/@/goldberg/@/paper.pdf, What Every Computer
+@uref{https://@/www.validlab.com/@/goldberg/@/paper.pdf, What Every Computer
Scientist Should Know About Floating-Point Arithmetic}.
@node Exiting Portably
@defmac AC_SCO_INTL
@acindex{SCO_INTL}
@ovindex LIBS
-If on SCO Unix, add @option{-lintl} to output variable @code{LIBS}. This
-macro used to do this:
-
-@example
-AC_CHECK_LIB([intl], [strftime], [LIBS="-lintl $LIBS"])
-@end example
-
-@noindent
-Now it just calls @code{AC_FUNC_STRFTIME} instead (@pxref{AC_FUNC_STRFTIME}).
+Equivalent to the obsolescent macro @code{AC_FUNC_STRFTIME}.
+@xref{AC_FUNC_STRFTIME}.
@end defmac
@defmac AC_SETVBUF_REVERSED
@defmac AC_XENIX_DIR
@acindex{XENIX_DIR}
@ovindex LIBS
-This macro used to add @option{-lx} to output variable @code{LIBS} if on
-Xenix. Also, if @file{dirent.h} is being checked for, added
-@option{-ldir} to @code{LIBS}. Now it is merely an alias of
-@code{AC_HEADER_DIRENT} instead, plus some code to detect whether
-running XENIX on which you should not depend:
-
-@example
-AC_MSG_CHECKING([for Xenix])
-AC_EGREP_CPP([yes],
-[#if defined M_XENIX && !defined M_UNIX
- yes
-#endif],
- [AC_MSG_RESULT([yes]); XENIX=yes],
- [AC_MSG_RESULT([no]); XENIX=])
-@end example
-@noindent
+This macro is equivalent to the obsolescent @code{AC_HEADER_DIRENT}
+macro, plus it also sets the shell variable @code{XENIX}.
Don't use this macro, the dignified means to check the nature of the
host is using @code{AC_CANONICAL_HOST} (@pxref{Canonicalizing}).
@end defmac
@item
Alternatively, you might use a shell with debugging capabilities like
-@uref{http://bashdb.sourceforge.net/, bashdb}.
+@uref{https://bashdb.sourceforge.net/, bashdb}.
@item
When @command{configure} tests produce invalid results for your system,
@c LocalWords: lstat rpl MEMCMP memcmp OpenStep MBRTOWC mbrtowc MKTIME mktime
@c LocalWords: localtime MMAP mmap OBSTACK obstack obstacks ARGTYPES timeval
@c LocalWords: SETPGRP setpgrp defmacx Hurd SETVBUF setvbuf STRCOLL strcoll
-@c LocalWords: STRTOD strtod DECL STRFTIME strftime SCO UTIME utime VPRINTF
+@c LocalWords: STRTOD strtod DECL STRFTIME strftime UTIME utime VPRINTF
@c LocalWords: DOPRNT vprintf doprnt sp unfixable LIBSOURCE LIBSOURCES Eggert
@c LocalWords: linux netinet ia Tru XFree DIRENT NDIR dirent ndir multitable
@c LocalWords: NAMLEN strlen namlen MKDEV SYSMACROS makedev RESOLV resolv DNS
@c LocalWords: yywrap xflex lexyy YFLAGS yacc divnum libs fuindex ffs
@c LocalWords: environ sigaction extern ftello nonnull STRTOLD LLONG
@c LocalWords: strtold vfprintf ULLONG strcasecmp strncasecmp MSVC th
-@c LocalWords: NDEBUG Xenix INO libc ISDIR ISREG Tektronix Amdahl ino
+@c LocalWords: NDEBUG INO libc ISDIR ISREG Tektronix Amdahl ino
@c LocalWords: typedef pxref fileblocks submembers INTMAX intmax UINT
@c LocalWords: INTPTR intptr SSIZE ssize uint UINTPTR uintptr OPENMP
@c LocalWords: openmp OpenMP omp Alignas Alignof Noreturn UTF vals gl