isnan: port to VAX

[gnulib.git] / m4 / fdatasync.m4

diff --git a/m4/fdatasync.m4 b/m4/fdatasync.m4
index cb11946..551c0d9 100644 (file)
--- a/m4/fdatasync.m4
+++ b/m4/fdatasync.m4
@@ -1,5 +1,5 @@
-# fdatasync.m4 serial 2
-dnl Copyright (C) 2008-2011 Free Software Foundation, Inc.
+# fdatasync.m4 serial 4
+dnl Copyright (C) 2008-2013 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.
@@ -7,13 +7,26 @@ dnl with or without modifications, as long as this notice is preserved.
 AC_DEFUN([gl_FUNC_FDATASYNC],
 [
   AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
-  AC_CHECK_FUNCS_ONCE([fdatasync])
-  if test $ac_cv_func_fdatasync = no; then
-    HAVE_FDATASYNC=0
-  fi
-  dnl MacOS X 10.7 has fdatasync but does not declare it.
+
+  dnl Using AC_CHECK_FUNCS_ONCE would break our subsequent AC_SEARCH_LIBS
   AC_CHECK_DECLS_ONCE([fdatasync])
+  LIB_FDATASYNC=
+  AC_SUBST([LIB_FDATASYNC])
+
   if test $ac_cv_have_decl_fdatasync = no; then
     HAVE_DECL_FDATASYNC=0
+    dnl Mac OS X 10.7 has fdatasync but does not declare it.
+    AC_CHECK_FUNCS([fdatasync])
+    if test $ac_cv_func_fdatasync = no; then
+      HAVE_FDATASYNC=0
+    fi
+  else
+    dnl Solaris <= 2.6 has fdatasync() in libposix4.
+    dnl Solaris 7..10 has it in librt.
+    gl_saved_libs=$LIBS
+    AC_SEARCH_LIBS([fdatasync], [rt posix4],
+                   [test "$ac_cv_search_fdatasync" = "none required" ||
+                    LIB_FDATASYNC=$ac_cv_search_fdatasync])
+    LIBS=$gl_saved_libs
   fi
 ])