Various minor changes on optee examples

Prefix test applications for the examples with 'optee_example_'.
Gitignore the generate test applications.
Few extra minor changes as make verbosity and source coding style.
STR_TRACE_USER_TA is deprecated.
Update README.

Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
Reviewed-by: Joakim Bech <joakim.bech@linaro.org>
diff --git a/Makefile b/Makefile
index 4d29a41..9fb6b46 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,9 @@
-export V?=0
+export V ?= 0
 
 OUTPUT_DIR := $(CURDIR)/out
-EXAMPLE_LIST := hello_world random
+
+EXAMPLE_LIST := hello_world
+EXAMPLE_LIST += random
 
 .PHONY: all
 all: examples prepare-for-rootfs
@@ -10,27 +12,28 @@
 clean: examples-clean prepare-for-rootfs-clean
 
 examples:
-	for example in $(EXAMPLE_LIST); do \
+	@for example in $(EXAMPLE_LIST); do \
 		$(MAKE) -C $$example CROSS_COMPILE="$(HOST_CROSS_COMPILE)"; \
 	done
 
 examples-clean:
-	for example in $(EXAMPLE_LIST); do \
+	@for example in $(EXAMPLE_LIST); do \
 		$(MAKE) -C $$example clean; \
 	done
 
 prepare-for-rootfs: examples
-	echo "Copying example CA and TA binaries to $(OUTPUT_DIR)..."
+	@echo "Copying example CA and TA binaries to $(OUTPUT_DIR)..."
 	@mkdir -p $(OUTPUT_DIR)
 	@mkdir -p $(OUTPUT_DIR)/ta
 	@mkdir -p $(OUTPUT_DIR)/ca
 	@for example in $(EXAMPLE_LIST); do \
-		if [ -e $$example/host/optee_$$example ]; then \
-			cp -p $$example/host/optee_$$example $(OUTPUT_DIR)/ca/; \
+		if [ -e $$example/host/optee_example_$$example ]; then \
+			cp -p $$example/host/optee_example_$$example $(OUTPUT_DIR)/ca/; \
 		fi; \
 		cp -pr $$example/ta/*.ta $(OUTPUT_DIR)/ta/; \
 	done
 
 prepare-for-rootfs-clean:
-	rm -rf $(OUTPUT_DIR)/ta/*
-	rm -rf $(OUTPUT_DIR)/ca/*
+	@rm -rf $(OUTPUT_DIR)/ta
+	@rm -rf $(OUTPUT_DIR)/ca
+	@rmdir --ignore-fail-on-non-empty $(OUTPUT_DIR) || test ! -e $(OUTPUT_DIR)