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Build: Add visibility.m4 from gnulib.

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Appears that this file used to get included as a side effect of
gettext. After the change to gettext version requirements this file
no longer got copied to the package and so the build was broken.
This commit is contained in:
Lasse Collin 2020-02-21 17:01:15 +02:00
parent 7fe3ef2eaa
commit 59e6eb4840
2 changed files with 77 additions and 1 deletions
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1
m4/.gitignore vendored
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@ -33,7 +33,6 @@ stdint_h.m4
threadlib.m4
uintmax_t.m4
ulonglong.m4
visibility.m4
wchar_t.m4
wint_t.m4
xsize.m4

77
m4/visibility.m4 Normal file
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@ -0,0 +1,77 @@
# visibility.m4 serial 6
dnl Copyright (C) 2005, 2008, 2010-2020 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
dnl From Bruno Haible.
dnl Tests whether the compiler supports the command-line option
dnl -fvisibility=hidden and the function and variable attributes
dnl __attribute__((__visibility__("hidden"))) and
dnl __attribute__((__visibility__("default"))).
dnl Does *not* test for __visibility__("protected") - which has tricky
dnl semantics (see the 'vismain' test in glibc) and does not exist e.g. on
dnl Mac OS X.
dnl Does *not* test for __visibility__("internal") - which has processor
dnl dependent semantics.
dnl Does *not* test for #pragma GCC visibility push(hidden) - which is
dnl "really only recommended for legacy code".
dnl Set the variable CFLAG_VISIBILITY.
dnl Defines and sets the variable HAVE_VISIBILITY.
AC_DEFUN([gl_VISIBILITY],
[
AC_REQUIRE([AC_PROG_CC])
CFLAG_VISIBILITY=
HAVE_VISIBILITY=0
if test -n "$GCC"; then
dnl First, check whether -Werror can be added to the command line, or
dnl whether it leads to an error because of some other option that the
dnl user has put into $CC $CFLAGS $CPPFLAGS.
AC_CACHE_CHECK([whether the -Werror option is usable],
[gl_cv_cc_vis_werror],
[gl_save_CFLAGS="$CFLAGS"
CFLAGS="$CFLAGS -Werror"
AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM([[]], [[]])],
[gl_cv_cc_vis_werror=yes],
[gl_cv_cc_vis_werror=no])
CFLAGS="$gl_save_CFLAGS"
])
dnl Now check whether visibility declarations are supported.
AC_CACHE_CHECK([for simple visibility declarations],
[gl_cv_cc_visibility],
[gl_save_CFLAGS="$CFLAGS"
CFLAGS="$CFLAGS -fvisibility=hidden"
dnl We use the option -Werror and a function dummyfunc, because on some
dnl platforms (Cygwin 1.7) the use of -fvisibility triggers a warning
dnl "visibility attribute not supported in this configuration; ignored"
dnl at the first function definition in every compilation unit, and we
dnl don't want to use the option in this case.
if test $gl_cv_cc_vis_werror = yes; then
CFLAGS="$CFLAGS -Werror"
fi
AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM(
[[extern __attribute__((__visibility__("hidden"))) int hiddenvar;
extern __attribute__((__visibility__("default"))) int exportedvar;
extern __attribute__((__visibility__("hidden"))) int hiddenfunc (void);
extern __attribute__((__visibility__("default"))) int exportedfunc (void);
void dummyfunc (void) {}
]],
[[]])],
[gl_cv_cc_visibility=yes],
[gl_cv_cc_visibility=no])
CFLAGS="$gl_save_CFLAGS"
])
if test $gl_cv_cc_visibility = yes; then
CFLAG_VISIBILITY="-fvisibility=hidden"
HAVE_VISIBILITY=1
fi
fi
AC_SUBST([CFLAG_VISIBILITY])
AC_SUBST([HAVE_VISIBILITY])
AC_DEFINE_UNQUOTED([HAVE_VISIBILITY], [$HAVE_VISIBILITY],
[Define to 1 or 0, depending whether the compiler supports simple visibility declarations.])
])