backupfile: initialize default suffix within the implementation

* lib/backupfile.c (find_backup_file_name): Initialize the
global variable here, to simplify usage, and to only call
getenv() when needed.

1 files changed, 11 insertions, 1 deletions

diff --git a/lib/backupfile.c b/lib/backupfile.c
index 1fe369eda5..780d2c9c1f 100644
--- a/lib/backupfile.c
+++ b/lib/backupfile.c
@@ -80,7 +80,7 @@
 
 /* The extension added to file names to produce a simple (as opposed
    to numbered) backup file name. */
-char const *simple_backup_suffix = "~";
+char const *simple_backup_suffix = NULL;
 
 
 /* If FILE (which was of length FILELEN before an extension was
@@ -268,6 +268,16 @@ find_backup_file_name (char const *file, enum backup_type backup_type)
   size_t ssize;
   bool simple = true;
 
+  /* Initialize the default simple backup suffix.  */
+  if (! simple_backup_suffix)
+    {
+      char const *env_suffix = getenv ("SIMPLE_BACKUP_SUFFIX");
+      if (env_suffix && *env_suffix)
+        simple_backup_suffix = env_suffix;
+      else
+        simple_backup_suffix = "~";
+    }
+
   /* Allow room for simple or ".~N~" backups.  The guess must be at
      least sizeof ".~1~", but otherwise will be adjusted as needed.  */
   size_t simple_backup_suffix_size = strlen (simple_backup_suffix) + 1;