Make:Use environment variables for OS detection.
Add make helper files to select the appropriate settings for the build
environment. Selection is made in make_helpers/build_env.mk, which
selects other files to include using generic build environment settings.
The Trusted Firmware Makefile and supporting tool Makefiles are updated
to include build_env.mk instead of unix.mk.
NOTE: This change does not fully enable builds in other build
environments. It facilitates this without compromising the
existing build environments.
Change-Id: Ic4064ffe6ce158bbd16d7cc9f27dd4655a3580f6
diff --git a/make_helpers/build_macros.mk b/make_helpers/build_macros.mk
index 42e11b3..5a67c4c 100644
--- a/make_helpers/build_macros.mk
+++ b/make_helpers/build_macros.mk
@@ -291,7 +291,7 @@
# NOTE: The line continuation '\' is required in the next define otherwise we
# end up with a line-feed characer at the end of the last c filename.
-# Also bare this issue in mind if extending the list of supported filetypes.
+# Also bear this issue in mind if extending the list of supported filetypes.
define SOURCES_TO_OBJS
$(notdir $(patsubst %.c,%.o,$(filter %.c,$(1)))) \
$(notdir $(patsubst %.S,%.o,$(filter %.S,$(1))))