docs/Makefile: use conditional assignment on sphinx variables
If 'makefile' variables are expected to be overwritten by environment
and/or command line, it is better to use conditional assignment ('?=')
so it clearly indicates the variable intention and usage.
Change-Id: I890f71fe4bb26b5777b49e9904a1489ca8fad498
Signed-off-by: Leonardo Sandoval <leonardo.sandoval@linaro.org>
diff --git a/docs/Makefile b/docs/Makefile
index a7083fb..5691e6c 100644
--- a/docs/Makefile
+++ b/docs/Makefile
@@ -1,5 +1,5 @@
#
-# Copyright (c) 2019, ARM Limited. All rights reserved.
+# Copyright (c) 2019-2020, ARM Limited. All rights reserved.
#
# SPDX-License-Identifier: BSD-3-Clause
#
@@ -7,11 +7,11 @@
#
# You can set these variables from the command line.
-SPHINXOPTS =
-SPHINXBUILD = sphinx-build
-SPHINXPROJ = TrustedFirmware-A Tests
-SOURCEDIR = .
-BUILDDIR = build
+SPHINXOPTS ?=
+SPHINXBUILD ?= sphinx-build
+SPHINXPROJ ?= TrustedFirmware-A Tests
+SOURCEDIR ?= $(CURDIR)
+BUILDDIR ?= build
# Put it first so that "make" without argument is like "make help".
help: