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

src/pcm/Clamp.hxx

@@ -4,8 +4,6 @@
 #ifndef MPD_PCM_UTILS_H
 #define MPD_PCM_UTILS_H
 
-#include "util/Compiler.h"
-
 #include <cstdint>
 #include <limits>
 
@@ -26,10 +24,10 @@ PcmClamp(typename Traits::long_type x) noexcept
 	static_assert(Traits::MIN >= limits::min(), "out of range");
 	static_assert(Traits::MAX <= limits::max(), "out of range");
 
-	if (gcc_unlikely(x < Traits::MIN))
+	if (x < Traits::MIN) [[unlikely]]
 		return T(Traits::MIN);
 
-	if (gcc_unlikely(x > Traits::MAX))
+	if (x > Traits::MAX) [[unlikely]]
 		return T(Traits::MAX);
 
 	return T(x);

src/pcm/Mix.hxx

@@ -5,7 +5,6 @@
 #define MPD_PCM_MIX_HXX
 
 #include "SampleFormat.hxx"
-#include "util/Compiler.h"
 
 #include <cstddef>
 

src/pcm/Pack.cxx

@@ -43,8 +43,7 @@ ConstructS24(uint8_t low, uint8_t mid, uint8_t high) noexcept
 /**
  * Read a packed signed little-endian 24 bit integer.
  */
-gcc_pure
-static int32_t
+static constexpr int32_t
 ReadS24LE(const uint8_t *src) noexcept
 {
 	return ConstructS24(src[0], src[1], src[2]);
@@ -53,8 +52,7 @@ ReadS24LE(const uint8_t *src) noexcept
 /**
  * Read a packed signed big-endian 24 bit integer.
  */
-gcc_pure
-static int32_t
+static constexpr int32_t
 ReadS24BE(const uint8_t *src) noexcept
 {
 	return ConstructS24(src[2], src[1], src[0]);
@@ -63,7 +61,7 @@ ReadS24BE(const uint8_t *src) noexcept
 /**
  * Read a packed signed native-endian 24 bit integer.
  */
-gcc_pure
+[[gnu::pure]]
 static int32_t
 ReadS24(const uint8_t *src) noexcept
 {

src/pcm/Resampler.hxx

@@ -4,8 +4,6 @@
 #ifndef MPD_PCM_RESAMPLER_HXX
 #define MPD_PCM_RESAMPLER_HXX
 
-#include "util/Compiler.h"
-
 #include <cstddef>
 #include <span>
 

src/pcm/SoxrResampler.cxx

@@ -48,8 +48,7 @@ static constexpr struct {
 	{ SOXR_INVALID_RECIPE, nullptr }
 };
 
-gcc_const
-static const char *
+static constexpr const char *
 soxr_quality_name(unsigned long recipe) noexcept
 {
 	for (const auto *i = soxr_quality_table;; ++i) {
@@ -60,7 +59,7 @@ soxr_quality_name(unsigned long recipe) noexcept
 	}
 }
 
-gcc_pure
+[[gnu::pure]]
 static unsigned long
 soxr_parse_quality(const char *quality) noexcept
 {