[NaCl SDK] Always use cmd.exe for SHELL in Windows Makefiles

native_client_sdk/src/tools/common.mk

 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 #
 # GNU Make based build file.  For details on GNU Make see:
 #   http://www.gnu.org/software/make/manual/make.html
 #
 
 #
@@ skipping 124 matching lines @@
 # have a preference for POSIX style command-line arguments.
 #
 # Keep in mind however that the shell is responsible for command-line escaping,
 # globbing, and variable expansion, so those may change based on which shell
 # is used.  For Cygwin shells this can include automatic and incorrect expansion
 # of response files (files starting with '@').
 #
 # Disable DOS PATH warning when using Cygwin based NaCl tools on Windows.
 #
 ifeq ($(OSNAME),win)
-  CYGWIN?=nodosfilewarning
+  # Always use cmd.exe as the shell on Windows. Otherwise Make may try to
+  # search the path for sh.exe. If it is found in a path with a space, the
+  # command will fail.
+  SHELL := cmd.exe
+  CYGWIN ?= nodosfilewarning
   export CYGWIN
 endif
 
 
 #
 # If NACL_SDK_ROOT is not already set, then set it relative to this makefile.
 #
 THIS_MAKEFILE := $(CURDIR)/$(lastword $(MAKEFILE_LIST))
 NACL_SDK_ROOT ?= $(realpath $(dir $(THIS_MAKEFILE))/..)
 
@@ skipping 376 matching lines @@
 # uppercase aliases (for backward compatibility)
 .PHONY: CHECK_FOR_CHROME DEBUG LAUNCH RUN
 CHECK_FOR_CHROME: check_for_chrome
 DEBUG: debug
 LAUNCH: run
 RUN: run
 
 endif  # TOOLCHAIN is valid...
 
 endif  # TOOLCHAIN=all