build(encrypt-fw): don't generate build_msg.c

This change avoids generating a build message source file on the shell,
instead using the `__DATE__` and `__TIME__` macros directly.

Change-Id: Ida537d4c3e550f2fbbd977472ed6573491d17c23
Signed-off-by: Chris Kay <chris.kay@arm.com>

changelog.yaml

@@ -1416,6 +1416,9 @@ subsections:
       - title: Certificate Creation Tool
         scope: cert-create
 
+      - title: Firmware Encryption Tool
+        scope: encrypt-fw
+
       - title: Memory Mapping Tool
         scope: memmap
 

tools/encrypt_fw/Makefile

@@ -1,4 +1,5 @@
 #
+# Copyright (c) 2024, Arm Limited. All rights reserved.
 # Copyright (c) 2019-2022, Linaro Limited. All rights reserved.
 #
 # SPDX-License-Identifier: BSD-3-Clause
@@ -64,9 +65,7 @@ all: --openssl ${BINARY}
 
 ${BINARY}: ${OBJECTS} Makefile
 	$(s)echo "  HOSTLD  $@"
-	$(q)echo 'const char build_msg[] = "Built : "__TIME__", "__DATE__;' | \
-                $(host-cc) -c ${HOSTCCFLAGS} -xc - -o src/build_msg.o
-	$(q)$(host-cc) src/build_msg.o ${OBJECTS} ${LIB_DIR} ${LIB} -o $@
+	$(q)$(host-cc) ${OBJECTS} ${LIB_DIR} ${LIB} -o $@
 
 %.o: %.c
 	$(s)echo "  HOSTCC  $<"
@@ -78,7 +77,7 @@ ifeq ($(DEBUG),1)
 endif
 
 clean:
-	$(call SHELL_DELETE_ALL, src/build_msg.o ${OBJECTS})
+	$(call SHELL_DELETE_ALL,${OBJECTS})
 
 realclean: clean
 	$(call SHELL_DELETE,${BINARY})

tools/encrypt_fw/src/main.c

@@ -1,4 +1,5 @@
 /*
+ * Copyright (c) 2024, Arm Limited and Contributors. All rights reserved.
  * Copyright (c) 2019, Linaro Limited. All rights reserved.
  * Author: Sumit Garg <sumit.garg@linaro.org>
  *
@@ -25,8 +26,7 @@
 
 /* Global options */
 
-/* Info messages created in the Makefile */
-extern const char build_msg[];
+static const char build_msg[] = "Built : " __TIME__ ", " __DATE__;
 
 static char *key_algs_str[] = {
 	[KEY_ALG_GCM] = "gcm",