Make:Make shell commands more portable

Macros are inserted to replace direct invocations of commands that are
problematic on some build environments. (e.g. Some environments expect
\ in paths instead of /.)
The changes take into account mismatched command mappings across
environments.
The new helper file unix.mk retains existing makefile behaviour on unix
like build environments by providing the following macro definitions:
  SHELL_COPY        cp -f
  SHELL_COPY_TREE   cp -rf
  SHELL_DELETE      rm -f
  SHELL_DELETE_ALL  rm -rf
  MAKE_PREREQ_DIR   mkdir -p  (As make target)
  SHELL_REMOVE_DIR  rm -rf

Change-Id: I1b5ca5e1208e78230b15284c4af00c1c006cffcb
diff --git a/make_helpers/unix.mk b/make_helpers/unix.mk
new file mode 100644
index 0000000..ab60435
--- /dev/null
+++ b/make_helpers/unix.mk
@@ -0,0 +1,81 @@
+#
+# Copyright (c) 2016, ARM Limited and Contributors. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# Redistributions of source code must retain the above copyright notice, this
+# list of conditions and the following disclaimer.
+#
+# Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# Neither the name of ARM nor the names of its contributors may be used
+# to endorse or promote products derived from this software without specific
+# prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+#
+#
+
+# Trusted Firmware shell command definitions for a Unix style environment.
+
+ifndef UNIX_MK
+    UNIX_MK := $(lastword $(MAKEFILE_LIST))
+
+    ECHO_BLANK_LINE := echo
+
+    DIR_DELIM := /
+    PATH_SEP := :
+
+    # These defines provide Unix style equivalents of the shell commands
+    # required by the Trusted Firmware build environment.
+
+    # ${1} is the file to be copied.
+    # ${2} is the destination file name.
+    define SHELL_COPY
+	${Q}cp -f  "${1}"  "${2}"
+    endef
+
+    # ${1} is the directory to be copied.
+    # ${2} is the destination directory path.
+    define SHELL_COPY_TREE
+	${Q}cp -rf  "${1}"  "${2}"
+    endef
+
+    # ${1} is the file to be deleted.
+    define SHELL_DELETE
+	-${Q}rm -f  "${1}"
+    endef
+
+    # ${1} is a space delimited list of files to be deleted.
+    # Note that we do not quote ${1}, as multiple parameters may be passed.
+    define SHELL_DELETE_ALL
+	-${Q}rm -rf  ${1}
+    endef
+
+    # ${1} is the directory to be generated.
+    # ${2} is optional, and allows a prerequisite to be specified.
+    define MAKE_PREREQ_DIR
+
+${1} : ${2}
+	${Q}mkdir -p  "${1}"
+
+    endef
+
+    define SHELL_REMOVE_DIR
+	-${Q}rm -rf  "${1}"
+    endef
+
+endif