Ensure that HAVE_* variables are set to 1 before they are set to 0.

[gnulib.git] / m4 / ceill.m4

diff --git a/m4/ceill.m4 b/m4/ceill.m4
index 71ac74f..40adaf1 100644 (file)
--- a/m4/ceill.m4
+++ b/m4/ceill.m4
@@ -1,4 +1,4 @@
-# ceill.m4 serial 8
+# ceill.m4 serial 11
 dnl Copyright (C) 2007, 2009-2011 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -11,7 +11,7 @@ AC_DEFUN([gl_FUNC_CEILL],
   dnl Persuade glibc <math.h> to declare ceill().
   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
   dnl Test whether ceill() is declared.
-  AC_CHECK_DECLS([ceill], , , [#include <math.h>])
+  AC_CHECK_DECLS([ceill], , , [[#include <math.h>]])
   if test "$ac_cv_have_decl_ceill" = yes; then
     dnl Test whether ceill() can be used without libm.
     gl_FUNC_CEILL_LIBS
@@ -35,10 +35,12 @@ AC_DEFUN([gl_FUNC_CEILL],
 #include <math.h>
 ]gl_LONG_DOUBLE_MINUS_ZERO_CODE[
 ]gl_LONG_DOUBLE_SIGNBIT_CODE[
-int main()
+static long double dummy (long double f) { return 0; }
+int main (int argc, char *argv[])
 {
+  long double (*my_ceill) (long double) = argc ? ceill : dummy;
   /* Test whether ceill (-0.3L) is -0.0L.  */
-  if (signbitl (minus_zerol) && !signbitl (ceill (-0.3L)))
+  if (signbitl (minus_zerol) && !signbitl (my_ceill (-0.3L)))
     return 1;
   return 0;
 }
@@ -58,7 +60,7 @@ int main()
     HAVE_DECL_CEILL=0
   fi
   if test $HAVE_DECL_CEILL = 0 || test $REPLACE_CEILL = 1; then
-    AC_LIBOBJ([ceill])
+    dnl No libraries are needed to link lib/ceill.c.
     CEILL_LIBM=
   fi
   AC_SUBST([CEILL_LIBM])