diff -up patch-2.6.1/src/patch.c.backup-if-mismatch patch-2.6.1/src/patch.c

--- patch-2.6.1/src/patch.c.backup-if-mismatch	2011-02-16 16:43:54.575850844 +0000

+++ patch-2.6.1/src/patch.c	2011-02-16 16:44:56.907995789 +0000

@@ -106,6 +106,7 @@ main (int argc, char **argv)

     char numbuf[LINENUM_LENGTH_BOUND + 1];

     bool written_to_rejname = false;

     bool apply_empty_patch = false;

+    bool posixly_correct_set;

     exit_failure = 2;

     program_name = argv[0];

@@ -125,7 +126,7 @@ main (int argc, char **argv)

 			 i < 0 ? shell_quoting_style : (enum quoting_style) i);

     }

-    posixly_correct = getenv ("POSIXLY_CORRECT") != 0;

+    posixly_correct_set = posixly_correct = getenv ("POSIXLY_CORRECT") != 0;

     backup_if_mismatch = ! posixly_correct;

     patch_get = ((val = getenv ("PATCH_GET"))

 		 ? numeric_string (val, true, "PATCH_GET value")

@@ -151,6 +152,10 @@ main (int argc, char **argv)

     Argv = argv;

     get_some_switches();

+    /* Let --posix cause --no-backup-if-mismatch. */

+    if (! posixly_correct_set && posixly_correct && backup_if_mismatch)

+      backup_if_mismatch = false;

+

     if (make_backups | backup_if_mismatch)

       backup_type = get_version (version_control_context, version_control);