use [[gnu::...]] attributes

src/db/update/InotifyUpdate.cxx

@@ -14,7 +14,6 @@
 #include "fs/FileInfo.hxx"
 #include "fs/Traits.hxx"
 #include "thread/Mutex.hxx"
-#include "util/Compiler.h"
 #include "Log.hxx"
 
 #include <cassert>
@@ -61,10 +60,10 @@ struct WatchDirectory {
 
 	void LoadExcludeList(Path directory_path) noexcept;
 
-	[[nodiscard]] gcc_pure
+	[[nodiscard]] [[gnu::pure]]
 	unsigned GetDepth() const noexcept;
 
-	[[nodiscard]] gcc_pure
+	[[nodiscard]] [[gnu::pure]]
 	AllocatedPath GetUriFS() const noexcept;
 };
 
@@ -137,7 +136,7 @@ WatchDirectory::GetUriFS() const noexcept
 }
 
 /* we don't look at "." / ".." nor files with newlines in their name */
-gcc_pure
+[[gnu::pure]]
 static bool
 SkipFilename(Path name) noexcept
 {
@@ -210,7 +209,7 @@ try {
 	LogError(std::current_exception());
 }
 
-gcc_pure
+[[gnu::pure]]
 unsigned
 WatchDirectory::GetDepth() const noexcept
 {

src/db/update/SpecialDirectory.cxx

@@ -7,7 +7,7 @@
 #include "playlist/PlaylistRegistry.hxx"
 #include "fs/Traits.hxx"
 
-gcc_pure
+[[gnu::pure]]
 static bool
 HaveArchivePluginForFilename(const char *filename) noexcept
 {
@@ -21,7 +21,7 @@ HaveArchivePluginForFilename(const char *filename) noexcept
 #endif
 }
 
-gcc_pure
+[[gnu::pure]]
 static bool
 HaveContainerPluginForFilename(const char *filename) noexcept
 {
@@ -31,7 +31,7 @@ HaveContainerPluginForFilename(const char *filename) noexcept
 		decoder_plugins_supports_suffix(suffix);
 }
 
-gcc_pure
+[[gnu::pure]]
 static bool
 HavePlaylistPluginForFilename(const char *filename) noexcept
 {

src/db/update/Walk.cxx

@@ -215,14 +215,14 @@ try {
 }
 
 /* we don't look at files with newlines in their name */
-gcc_pure
+[[gnu::pure]]
 static bool
 skip_path(const char *name_utf8) noexcept
 {
 	return std::strchr(name_utf8, '\n') != nullptr;
 }
 
-gcc_pure
+[[gnu::pure]]
 bool
 UpdateWalk::SkipSymlink(const Directory *directory,
 			std::string_view utf8_name) const noexcept