logl: Simplify for platforms where 'long double' == 'double'.

* lib/logl.c (logl) [HAVE_SAME_LONG_DOUBLE_AS_DOUBLE]: New alternative
implementation.
* m4/logl.m4 (gl_FUNC_LOGL): Require gl_LONG_DOUBLE_VS_DOUBLE.
Determine LOGL_LIBM according to HAVE_SAME_LONG_DOUBLE_AS_DOUBLE.
* modules/logl (Depends-on): Add log. Update conditions.

1 files changed, 26 insertions, 19 deletions

diff --git a/m4/logl.m4 b/m4/logl.m4
index 70a5eadfc6..f17e5e5f3f 100644
--- a/m4/logl.m4
+++ b/m4/logl.m4
@@ -1,4 +1,4 @@
-# logl.m4 serial 5
+# logl.m4 serial 6
 dnl Copyright (C) 2010-2011 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -7,6 +7,8 @@ dnl with or without modifications, as long as this notice is preserved.
 AC_DEFUN([gl_FUNC_LOGL],
 [
   AC_REQUIRE([gl_MATH_H_DEFAULTS])
+  AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE])
+
   dnl Persuade glibc <math.h> to declare logl().
   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
 
@@ -56,24 +58,29 @@ AC_DEFUN([gl_FUNC_LOGL],
     HAVE_DECL_LOGL=0
     HAVE_LOGL=0
     dnl Find libraries needed to link lib/logl.c.
-    AC_REQUIRE([gl_FUNC_FREXPL])
-    AC_REQUIRE([gl_FUNC_ISNANL])
-    AC_REQUIRE([gl_FUNC_FLOORL])
-    dnl Append $FREXPL_LIBM to LOGL_LIBM, avoiding gratuitous duplicates.
-    case " $LOGL_LIBM " in
-      *" $FREXPL_LIBM "*) ;;
-      *) LOGL_LIBM="$LOGL_LIBM $FREXPL_LIBM" ;;
-    esac
-    dnl Append $ISNANL_LIBM to LOGL_LIBM, avoiding gratuitous duplicates.
-    case " $LOGL_LIBM " in
-      *" $ISNANL_LIBM "*) ;;
-      *) LOGL_LIBM="$LOGL_LIBM $ISNANL_LIBM" ;;
-    esac
-    dnl Append $FLOORL_LIBM to LOGL_LIBM, avoiding gratuitous duplicates.
-    case " $LOGL_LIBM " in
-      *" $FLOORL_LIBM "*) ;;
-      *) LOGL_LIBM="$LOGL_LIBM $FLOORL_LIBM" ;;
-    esac
+    if test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1; then
+      AC_REQUIRE([gl_FUNC_LOG])
+      LOGL_LIBM="$LOG_LIBM"
+    else
+      AC_REQUIRE([gl_FUNC_FREXPL])
+      AC_REQUIRE([gl_FUNC_ISNANL])
+      AC_REQUIRE([gl_FUNC_FLOORL])
+      dnl Append $FREXPL_LIBM to LOGL_LIBM, avoiding gratuitous duplicates.
+      case " $LOGL_LIBM " in
+        *" $FREXPL_LIBM "*) ;;
+        *) LOGL_LIBM="$LOGL_LIBM $FREXPL_LIBM" ;;
+      esac
+      dnl Append $ISNANL_LIBM to LOGL_LIBM, avoiding gratuitous duplicates.
+      case " $LOGL_LIBM " in
+        *" $ISNANL_LIBM "*) ;;
+        *) LOGL_LIBM="$LOGL_LIBM $ISNANL_LIBM" ;;
+      esac
+      dnl Append $FLOORL_LIBM to LOGL_LIBM, avoiding gratuitous duplicates.
+      case " $LOGL_LIBM " in
+        *" $FLOORL_LIBM "*) ;;
+        *) LOGL_LIBM="$LOGL_LIBM $FLOORL_LIBM" ;;
+      esac
+    fi
   fi
   AC_SUBST([LOGL_LIBM])
 ])