From f4e8084414e07a8e03cb279090bbcf9eea76ed1e Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Wed, 15 Nov 2023 10:04:57 -0500
Subject: config: New attr_maybe_unused macro

---
 src/config.h | 13 ++++++++++++-
 src/fsade.c  |  7 +++----
 src/mtab.c   |  3 ++-
 src/xspawn.c |  3 ++-
 4 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/src/config.h b/src/config.h
index a474fb3..9f95674 100644
--- a/src/config.h
+++ b/src/config.h
@@ -186,7 +186,7 @@ typedef long double max_align_t;
 // Wrappers for attributes
 
 /**
- * Silence compiler warnings about switch/case fall-throughs.
+ * Silence warnings about switch/case fall-throughs.
  */
 #if __has_c_attribute(fallthrough)
 #  define fallthru [[fallthrough]]
@@ -196,6 +196,17 @@ typedef long double max_align_t;
 #  define fallthru ((void)0)
 #endif
 
+/**
+ * Silence warnings about unused declarations.
+ */
+#if __has_c_attribute(maybe_unused)
+#  define attr_maybe_unused [[maybe_unused]]
+#elif __has_attribute(unused)
+#  define attr_maybe_unused __attribute__((unused))
+#else
+#  define attr_maybe_unused
+#endif
+
 /**
  * Warn if a value is unused.
  */
diff --git a/src/fsade.c b/src/fsade.c
index cbff47b..4d22d99 100644
--- a/src/fsade.c
+++ b/src/fsade.c
@@ -28,12 +28,11 @@
 #  include <sys/xattr.h>
 #endif
 
-#if BFS_CAN_CHECK_ACL || BFS_CAN_CHECK_CAPABILITIES || BFS_CAN_CHECK_XATTRS
-
 /**
  * Many of the APIs used here don't have *at() variants, but we can try to
  * emulate something similar if /proc/self/fd is available.
  */
+attr_maybe_unused
 static const char *fake_at(const struct BFTW *ftwbuf) {
 	static atomic int proc_works = -1;
 
@@ -67,6 +66,7 @@ fail:
 	return ftwbuf->path;
 }
 
+attr_maybe_unused
 static void free_fake_at(const struct BFTW *ftwbuf, const char *path) {
 	if (path != ftwbuf->path) {
 		dstrfree((dchar *)path);
@@ -76,6 +76,7 @@ static void free_fake_at(const struct BFTW *ftwbuf, const char *path) {
 /**
  * Check if an error was caused by the absence of support or data for a feature.
  */
+attr_maybe_unused
 static bool is_absence_error(int error) {
 	// If the OS doesn't support the feature, it's obviously not enabled for
 	// any files
@@ -114,8 +115,6 @@ static bool is_absence_error(int error) {
 	return false;
 }
 
-#endif // BFS_CAN_CHECK_ACL || BFS_CAN_CHECK_CAPABILITIES || BFS_CAN_CHECK_XATTRS
-
 #if BFS_CAN_CHECK_ACL
 
 /** Check if a POSIX.1e ACL is non-trivial. */
diff --git a/src/mtab.c b/src/mtab.c
index 384fdfc..6b6f9d1 100644
--- a/src/mtab.c
+++ b/src/mtab.c
@@ -59,7 +59,8 @@ struct bfs_mtab {
 /**
  * Add an entry to the mount table.
  */
-static inline int bfs_mtab_add(struct bfs_mtab *mtab, const char *path, const char *type) {
+attr_maybe_unused
+static int bfs_mtab_add(struct bfs_mtab *mtab, const char *path, const char *type) {
 	struct bfs_mtab_entry entry = {
 		.path = strdup(path),
 		.type = strdup(type),
diff --git a/src/xspawn.c b/src/xspawn.c
index 3974768..51432dd 100644
--- a/src/xspawn.c
+++ b/src/xspawn.c
@@ -73,7 +73,8 @@ int bfs_spawn_destroy(struct bfs_spawn *ctx) {
 }
 
 /** Set some posix_spawnattr flags. */
-static inline int bfs_spawn_addflags(struct bfs_spawn *ctx, short flags) {
+attr_maybe_unused
+static int bfs_spawn_addflags(struct bfs_spawn *ctx, short flags) {
 	short prev;
 	errno = posix_spawnattr_getflags(&ctx->attr, &prev);
 	if (errno != 0) {
-- 
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