Instead of relying on FreeBSD being the only system not having __environ stderr ___brk_addr and __ctype_b, look for them during ./configure stage. Also check for alternatives, and check for compiler's weak aliasing support only if it's actually going to be used.

CVS patchset: 8696
CVS date: 2007/03/17 06:11:30

1 files changed, 65 insertions, 0 deletions

diff --git a/m4/symbol.m4 b/m4/symbol.m4
new file mode 100644
index 000000000..cb31e193b
--- /dev/null
+++ b/m4/symbol.m4
@@ -0,0 +1,65 @@
+dnl Macros to check the presence of generic (non-typed) symbols.
+dnl Copyright (c) 2007 xine project
+dnl
+dnl This program is free software; you can redistribute it and/or modify
+dnl it under the terms of the GNU General Public License as published by
+dnl the Free Software Foundation; either version 2, or (at your option)
+dnl any later version.
+dnl
+dnl This program is distributed in the hope that it will be useful,
+dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
+dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+dnl GNU General Public License for more details.
+dnl
+dnl You should have received a copy of the GNU General Public License
+dnl along with this program; if not, write to the Free Software
+dnl Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+dnl 02110-1301, USA.
+dnl
+dnl As a special exception, the xine project, as copyright owner of the
+dnl macro gives unlimited permission to copy, distribute and modify the
+dnl configure scripts that are the output of Autoconf when processing the
+dnl Macro. You need not follow the terms of the GNU General Public
+dnl License when using or distributing such scripts, even though portions
+dnl of the text of the Macro appear in them. The GNU General Public
+dnl License (GPL) does govern all other use of the material that
+dnl constitutes the Autoconf Macro.
+dnl 
+dnl This special exception to the GPL applies to versions of the
+dnl Autoconf Macro released by the xine project. When you make and
+dnl distribute a modified version of the Autoconf Macro, you may extend
+dnl this special exception to the GPL to apply to your modified version as
+dnl well.
+
+dnl AC_CHECK_SYMBOL - Check for a single symbol
+dnl Usage: AC_CHECK_SYMBOL([symbol], [action-if-found], [action-if-not-found])
+dnl Default action, defines HAVE_SYMBOL (with symbol capitalised) if the
+dnl symbol is present at link time.
+AC_DEFUN([AC_CHECK_SYMBOL], [
+  AC_CACHE_CHECK([for $1 symbol presence],
+    AS_TR_SH([ac_cv_symbol_$1]),
+    [AC_TRY_LINK([extern void *$1;], [void *tmp = $1;],
+       [eval "AS_TR_SH([ac_cv_symbol_$1])=yes"],
+       [eval "AS_TR_SH([ac_cv_symbol_$1])=no"])
+    ])
+
+  ifelse([$2], , [AC_DEFINE_UNQUOTED(AS_TR_CPP([HAVE_$1]), [1], [Define to 1 if you have the $1 symbol.])], [$2])
+  ifelse([$3], , , [$3])
+])
+
+dnl AC_CHECK_SYMBOLS - Check for multiple symbols
+dnl Usage: AC_CHECK_SYMBOLS([symbol1 symbol2], [action-if-found], [action-if-not-found])
+AC_DEFUN([AC_CHECK_SYMBOLS], [
+  AH_CHECK_SYMBOLS([$1])
+
+  for ac_symbol in $1
+  do
+    AC_CHECK_SYMBOL($ac_symbol, [AC_DEFINE_UNQUOTED(AS_TR_CPP([HAVE_$ac_symbol])) $2], [$3])
+  done
+])
+
+m4_define([AH_CHECK_SYMBOLS], [
+  m4_foreach_w([AC_Symbol], [$1],
+   [AH_TEMPLATE(AS_TR_CPP([HAVE_]m4_defn([AC_Symbol])),
+      [Define to 1 if you have the ]m4_defn([AC_Symbol])[ symbol.])])
+])
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