[S] Change in coreboot[main]: symbols: Add __maybe_unused flag to region variable symbols

[Jérémy Compostella (Code Review)]

Jérémy Compostella has submitted this change. ( https://review.coreboot.org/c/coreboot/+/81209?usp=email )

(

4 is the latest approved patch-set.
No files were changed between the latest approved patch-set and the submitted one.
 )Change subject: symbols: Add __maybe_unused flag to region variable symbols
......................................................................

symbols: Add __maybe_unused flag to region variable symbols

In DECLARE_REGION and DECLARE_OPTIONAL_REGION, a set of 3 variables
will be defined, that is the region 'base', 'end' and 'size'.
However, in many codes, the users will only selectively use 'end'
or 'size' instead of both of them, which will trigger compiler errors
for unused variables. This patch sets __maybe_unused attributes on
'end' and 'size' so that users do not need to use all of them.

TEST=intel/archercity CRB

Change-Id: Ia5ed183b2dd7a474ce51de47dbc1f9e3f61e5a41
Signed-off-by: Shuo Liu 
Reviewed-on: https://review.coreboot.org/c/coreboot/+/81209
Reviewed-by: Jérémy Compostella 
Reviewed-by: Julius Werner 
Reviewed-by: Martin L Roth 
Tested-by: build bot (Jenkins) 
---
M src/include/symbols.h
1 file changed, 6 insertions(+), 6 deletions(-)

Approvals:
  Julius Werner: Looks good to me, approved
  Martin L Roth: Looks good to me, approved
  build bot (Jenkins): Verified
  Jérémy Compostella: Looks good to me, but someone else must approve

diff --git a/src/include/symbols.h b/src/include/symbols.h
index b1e44e11..ef23814 100644
--- a/src/include/symbols.h
+++ b/src/include/symbols.h
@@ -10,9 +10,9 @@
 #define REGION_SIZE(name) ((size_t)_##name##_size)

#define DECLARE_REGION(name)	\
-	extern u8 _##name[];	\
-	extern u8 _e##name[];	\
-	extern u8 _##name##_size[];
+	__maybe_unused extern u8 _##name[];	\
+	__maybe_unused extern u8 _e##name[];	\
+	__maybe_unused extern u8 _##name##_size[];

/*
  * Regions can be declared optional if not all configurations provide them in
@@ -23,9 +23,9 @@
  * should then check (REGION_SIZE(name) != 0) before accessing it.
  */
 #define DECLARE_OPTIONAL_REGION(name)	\
-	__weak extern u8 _##name[];	\
-	__weak extern u8 _e##name[];	\
-	__weak extern u8 _##name##_size[];
+	__maybe_unused __weak extern u8 _##name[];	\
+	__maybe_unused __weak extern u8 _e##name[];	\
+	__maybe_unused __weak extern u8 _##name##_size[];

DECLARE_REGION(sram)
 DECLARE_OPTIONAL_REGION(timestamp)