X-Git-Url: https://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Fungetc.m4;h=4e3577a8a08c62309f56ca42c1f84a5e45a92915;hb=da8054d48dc22e1c051db54049e005d51a006e69;hp=eb652356b539a9f45a9903728470834138bc4b54;hpb=5ff811558adf7013f9fd9109fa794dd4e5ee8c91;p=gnulib.git

diff --git a/m4/ungetc.m4 b/m4/ungetc.m4
index eb652356b..4e3577a8a 100644
--- a/m4/ungetc.m4
+++ b/m4/ungetc.m4
@@ -1,5 +1,5 @@
-# ungetc.m4 serial 2
-dnl Copyright (C) 2009 Free Software Foundation, Inc.
+# ungetc.m4 serial 3
+dnl Copyright (C) 2009-2013 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.
@@ -7,30 +7,40 @@ dnl with or without modifications, as long as this notice is preserved.
 AC_DEFUN_ONCE([gl_FUNC_UNGETC_WORKS],
 [
   AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
 
   AC_CACHE_CHECK([whether ungetc works on arbitrary bytes],
     [gl_cv_func_ungetc_works],
     [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
 #include <stdio.h>
       ]], [FILE *f;
-	   if (!(f = fopen ("conftest.tmp", "w+"))) return 1;
-	   if (fputs ("abc", f) < 0) return 2;
-	   rewind (f);
-	   if (fgetc (f) != 'a') return 3;
-	   if (fgetc (f) != 'b') return 4;
-	   if (ungetc ('d', f) != 'd') return 5;
-	   if (ftell (f) != 1) return 6;
-	   if (fgetc (f) != 'd') return 7;
-	   if (ftell (f) != 2) return 8;
-	   if (fseek (f, 0, SEEK_CUR) != 0) return 9;
-	   if (ftell (f) != 2) return 10;
-	   if (fgetc (f) != 'c') return 11;
-	   fclose (f); remove ("conftest.tmp");])],
-	[gl_cv_func_ungetc_works=yes], [gl_cv_func_ungetc_works=no],
-	[gl_cv_func_ungetc_works='guessing no'])
+           if (!(f = fopen ("conftest.tmp", "w+"))) return 1;
+           if (fputs ("abc", f) < 0) return 2;
+           rewind (f);
+           if (fgetc (f) != 'a') return 3;
+           if (fgetc (f) != 'b') return 4;
+           if (ungetc ('d', f) != 'd') return 5;
+           if (ftell (f) != 1) return 6;
+           if (fgetc (f) != 'd') return 7;
+           if (ftell (f) != 2) return 8;
+           if (fseek (f, 0, SEEK_CUR) != 0) return 9;
+           if (ftell (f) != 2) return 10;
+           if (fgetc (f) != 'c') return 11;
+           fclose (f); remove ("conftest.tmp");])],
+        [gl_cv_func_ungetc_works=yes], [gl_cv_func_ungetc_works=no],
+        [case "$host_os" in
+                   # Guess yes on glibc systems.
+           *-gnu*) gl_cv_func_ungetc_works="guessing yes" ;;
+                   # If we don't know, assume the worst.
+           *)      gl_cv_func_ungetc_works="guessing no" ;;
+         esac
+        ])
     ])
-  if test "$gl_cv_func_ungetc_works" != yes; then
-    AC_DEFINE([FUNC_UNGETC_BROKEN], [1],
-      [Define to 1 if ungetc is broken when used on arbitrary bytes.])
-  fi
+  case "$gl_cv_func_ungetc_works" in
+    *yes) ;;
+    *)
+      AC_DEFINE([FUNC_UNGETC_BROKEN], [1],
+        [Define to 1 if ungetc is broken when used on arbitrary bytes.])
+      ;;
+  esac
 ])