MFC r322177: Respect SIMPLE_BACKUP_SUFFIX environment variable in indent(1)

Instead of using a non-configurable ".BAK" suffix, respect the
SIMPLE_BACKUP_SUFFIX environment variable also used by patch(1). This
simplifies cleanup operations in some patch/indent workflows.

2 files changed, 13 insertions, 4 deletions

diff --git a/usr.bin/indent/indent.1 b/usr.bin/indent/indent.1
index 60ae0bc..9e83538 100644
--- a/usr.bin/indent/indent.1
+++ b/usr.bin/indent/indent.1
@@ -30,7 +30,7 @@
 .\"	@(#)indent.1	8.1 (Berkeley) 7/1/93
 .\" $FreeBSD$
 .\"
-.Dd March 3, 2012
+.Dd August 7, 2017
 .Dt INDENT 1
 .Os
 .Sh NAME
@@ -113,7 +113,10 @@ If
 is named
 .Sq Pa /blah/blah/file ,
 the backup file is named
-.Sq Pa file.BAK .
+.Sq Pa file.BAK
+by default. The extension used for the backup file may be overridden using the
+.Ev SIMPLE_BACKUP_SUFFIX
+environment variable.
 .Pp
 If
 .Ar output-file
diff --git a/usr.bin/indent/indent.c b/usr.bin/indent/indent.c
index 7c2cbea..bc28079 100644
--- a/usr.bin/indent/indent.c
+++ b/usr.bin/indent/indent.c
@@ -68,6 +68,8 @@ const char *in_name = "Standard Input";	/* will always point to name of input
 					 * file */
 const char *out_name = "Standard Output";	/* will always point to name
 						 * of output file */
+const char *simple_backup_suffix = ".BAK";	/* Suffix to use for backup
+						 * files */
 char        bakfile[MAXPATHLEN] = "";
 
 int
@@ -94,7 +96,7 @@ main(int argc, char **argv)
     int         type_code;	/* the type of token, returned by lexi */
 
     int         last_else = 0;	/* true iff last keyword was an else */
-
+    const char *envval = NULL;
 
     /*-----------------------------------------------*\
     |		      INITIALIZATION		      |
@@ -154,6 +156,10 @@ main(int argc, char **argv)
     output = 0;
     tabs_to_var = 0;
 
+    envval = getenv("SIMPLE_BACKUP_SUFFIX");
+    if (envval)
+        simple_backup_suffix = envval;
+
     /*--------------------------------------------------*\
     |   		COMMAND LINE SCAN		 |
     \*--------------------------------------------------*/
@@ -1207,7 +1213,7 @@ bakcopy(void)
 	p--;
     if (*p == '/')
 	p++;
-    sprintf(bakfile, "%s.BAK", p);
+    sprintf(bakfile, "%s%s", p, simple_backup_suffix);
 
     /* copy in_name to backup file */
     bakchn = creat(bakfile, 0600);