bug#42415: Remove unused parallel mapper argument

[Francesco Montanari <fmnt@fmnt.info>]

 From 116cb3cc3ea8fc72fa99d0405ecbe04a2d0f3d96 Mon Sep 17 00:00:00 2001
From: Francesco Montanari <fmnt@fmnt.info>
Date: Sat, 18 Jul 2020 15:44:38 +0200
Subject: [PATCH] Remove unused parallel mapper argument

* module/ice-9/threads.scm (par-mapper, par-map, par-for-each): Remove
   unused `mapper` argument in `par-mapper` procedure.

This change does not modify the procedures behavior.
---
  module/ice-9/threads.scm | 6 +++---
  1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/module/ice-9/threads.scm b/module/ice-9/threads.scm
index c42bd266f..5b5ebaf4f 100644
--- a/module/ice-9/threads.scm
+++ b/module/ice-9/threads.scm
@@ -279,7 +279,7 @@ terminates, unless the target @var{thread} has 
already terminated."
      (lambda (v ...)
        b0 b1 ...)))

-(define (par-mapper mapper cons)
+(define (par-mapper cons)
    (lambda (proc . lists)
      (let loop ((lists lists))
        (match lists
@@ -290,8 +290,8 @@ terminates, unless the target @var{thread} has 
already terminated."
          (_
           '())))))

-(define par-map (par-mapper map cons))
-(define par-for-each (par-mapper for-each (const *unspecified*)))
+(define par-map (par-mapper cons))
+(define par-for-each (par-mapper (const *unspecified*)))

  (define (n-par-map n proc . arglists)
    (let* ((m (make-mutex))
-- 
2.20.1