[BUILD] Fixed build on OS X

Hi, Herbert and friends.  I've created a small patch that allows dash
to be built on Mac OS X.  I'm contributing it here with the hope that
it's suitable for inclusion in dash.

The changes in this patch are:

- __attribute__((__alias__())) is not supported, add an autoconf check
- open64 is not present although the stat64 family is, separate the
  autoconf checks
- A syntax error had slipped into a non-glibc codepath
- mkbuiltins had a nonportable mktemp invocation for the case where
  tempfile is not availalble

Nothing in this patch is actually Mac OS X-specific, so it might aid
portability to other platforms as well.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

ChangeLog

@@ -1,3 +1,7 @@
+2009-01-13  Mark Mentovai <mmentovai@gmail.com>
+
+	* Fixed build on OS X.
+
 2008-12-26  Aleksey Cheusov <vle@gmx.net>
 
 	* Fixed build on NetBSD.

configure.ac

@@ -18,6 +18,18 @@ fi
 AC_MSG_RESULT(${CC_FOR_BUILD})
 AC_SUBST(CC_FOR_BUILD)
 
+AC_MSG_CHECKING([for __attribute__((__alias__()))])
+dash_cv_have_attribute_alias=no
+AC_LINK_IFELSE([AC_LANG_PROGRAM([void t() {}
+                                 void a() __attribute__((__alias__("t")));],
+                                [a();])],
+               [dash_cv_have_attribute_alias=yes])
+AC_MSG_RESULT($dash_cv_have_attribute_alias)
+if test "x$dash_cv_have_attribute_alias" = xyes; then
+  AC_DEFINE([HAVE_ALIAS_ATTRIBUTE], 1,
+            [Define if __attribute__((__alias__())) is supported])
+fi
+
 AC_ARG_ENABLE(static, AS_HELP_STRING(--enable-static, \
 				     [Build statical linked program]))
 if test "$enable_static" = "yes"; then
@@ -60,6 +72,9 @@ AC_CHECK_FUNC(stat64,, [
 	AC_DEFINE(fstat64, fstat, [64-bit operations are the same as 32-bit])
 	AC_DEFINE(lstat64, lstat, [64-bit operations are the same as 32-bit])
 	AC_DEFINE(stat64, stat, [64-bit operations are the same as 32-bit])
+])
+
+AC_CHECK_FUNC(open64,, [
 	AC_DEFINE(open64, open, [64-bit operations are the same as 32-bit])
 ])
 

src/eval.c

@@ -326,7 +326,15 @@ exexit:
 #if !defined(__alpha__) || (defined(__GNUC__) && __GNUC__ >= 3)
 STATIC
 #endif
-void evaltreenr(union node *, int) __attribute__ ((alias("evaltree")));
+void evaltreenr(union node *n, int flags)
+#ifdef HAVE_ATTRIBUTE_ALIAS
+	__attribute__ ((alias("evaltree")));
+#else
+{
+	evaltree(n, flags);
+	abort();
+}
+#endif
 
 
 STATIC void

src/jobs.c

@@ -361,7 +361,14 @@ fgcmd(int argc, char **argv)
 	return retval;
 }
 
-int bgcmd(int, char **) __attribute__((__alias__("fgcmd")));
+int bgcmd(int argc, char **argv)
+#ifdef HAVE_ALIAS_ATTRIBUTE
+	__attribute__((__alias__("fgcmd")));
+#else
+{
+	return fgcmd(argc, argv);
+}
+#endif
 
 
 STATIC int