diff --git a/src/liblzma/common/alone_decoder.c b/src/liblzma/common/alone_decoder.c
index 039b4285..678c79e6 100644
--- a/src/liblzma/common/alone_decoder.c
+++ b/src/liblzma/common/alone_decoder.c
@@ -46,7 +46,7 @@ struct lzma_coder_s {
 
 static lzma_ret
 alone_decode(lzma_coder *coder,
-		lzma_allocator *allocator lzma_attribute((unused)),
+		lzma_allocator *allocator lzma_attribute((__unused__)),
 		const uint8_t *restrict in, size_t *restrict in_pos,
 		size_t in_size, uint8_t *restrict out,
 		size_t *restrict out_pos, size_t out_size,
diff --git a/src/liblzma/common/alone_encoder.c b/src/liblzma/common/alone_encoder.c
index 7f616557..eb1697e9 100644
--- a/src/liblzma/common/alone_encoder.c
+++ b/src/liblzma/common/alone_encoder.c
@@ -32,7 +32,7 @@ struct lzma_coder_s {
 
 static lzma_ret
 alone_encode(lzma_coder *coder,
-		lzma_allocator *allocator lzma_attribute((unused)),
+		lzma_allocator *allocator lzma_attribute((__unused__)),
 		const uint8_t *restrict in, size_t *restrict in_pos,
 		size_t in_size, uint8_t *restrict out,
 		size_t *restrict out_pos, size_t out_size,
diff --git a/src/liblzma/common/block_encoder.c b/src/liblzma/common/block_encoder.c
index b34c5013..1eeb502b 100644
--- a/src/liblzma/common/block_encoder.c
+++ b/src/liblzma/common/block_encoder.c
@@ -144,7 +144,7 @@ block_encoder_end(lzma_coder *coder, lzma_allocator *allocator)
 
 static lzma_ret
 block_encoder_update(lzma_coder *coder, lzma_allocator *allocator,
-		const lzma_filter *filters lzma_attribute((unused)),
+		const lzma_filter *filters lzma_attribute((__unused__)),
 		const lzma_filter *reversed_filters)
 {
 	if (coder->sequence != SEQ_CODE)
diff --git a/src/liblzma/common/common.c b/src/liblzma/common/common.c
index 0408e153..b9e38602 100644
--- a/src/liblzma/common/common.c
+++ b/src/liblzma/common/common.c
@@ -35,7 +35,7 @@ lzma_version_string(void)
 // Memory allocation //
 ///////////////////////
 
-extern void * lzma_attribute((malloc))
+extern void * lzma_attribute((__malloc__)) lzma_attr_alloc_size(1)
 lzma_alloc(size_t size, lzma_allocator *allocator)
 {
 	// Some malloc() variants return NULL if called with size == 0.
diff --git a/src/liblzma/common/common.h b/src/liblzma/common/common.h
index b8194323..45aba4f0 100644
--- a/src/liblzma/common/common.h
+++ b/src/liblzma/common/common.h
@@ -205,7 +205,7 @@ struct lzma_internal_s {
 
 /// Allocates memory
 extern void *lzma_alloc(size_t size, lzma_allocator *allocator)
-		lzma_attribute((malloc)) lzma_attr_alloc_size(1);
+		lzma_attribute((__malloc__)) lzma_attr_alloc_size(1);
 
 /// Frees memory
 extern void lzma_free(void *ptr, lzma_allocator *allocator);
diff --git a/src/liblzma/common/index_decoder.c b/src/liblzma/common/index_decoder.c
index a6bc650e..83c8a3af 100644
--- a/src/liblzma/common/index_decoder.c
+++ b/src/liblzma/common/index_decoder.c
@@ -56,10 +56,11 @@ struct lzma_coder_s {
 static lzma_ret
 index_decode(lzma_coder *coder, lzma_allocator *allocator,
 		const uint8_t *restrict in, size_t *restrict in_pos,
-		size_t in_size, uint8_t *restrict out lzma_attribute((unused)),
-		size_t *restrict out_pos lzma_attribute((unused)),
-		size_t out_size lzma_attribute((unused)),
-		lzma_action action lzma_attribute((unused)))
+		size_t in_size,
+		uint8_t *restrict out lzma_attribute((__unused__)),
+		size_t *restrict out_pos lzma_attribute((__unused__)),
+		size_t out_size lzma_attribute((__unused__)),
+		lzma_action action lzma_attribute((__unused__)))
 {
 	// Similar optimization as in index_encoder.c
 	const size_t in_start = *in_pos;
diff --git a/src/liblzma/common/index_encoder.c b/src/liblzma/common/index_encoder.c
index c10d7afa..45919f09 100644
--- a/src/liblzma/common/index_encoder.c
+++ b/src/liblzma/common/index_encoder.c
@@ -42,12 +42,13 @@ struct lzma_coder_s {
 
 static lzma_ret
 index_encode(lzma_coder *coder,
-		lzma_allocator *allocator lzma_attribute((unused)),
-		const uint8_t *restrict in lzma_attribute((unused)),
-		size_t *restrict in_pos lzma_attribute((unused)),
-		size_t in_size lzma_attribute((unused)),
+		lzma_allocator *allocator lzma_attribute((__unused__)),
+		const uint8_t *restrict in lzma_attribute((__unused__)),
+		size_t *restrict in_pos lzma_attribute((__unused__)),
+		size_t in_size lzma_attribute((__unused__)),
 		uint8_t *restrict out, size_t *restrict out_pos,
-		size_t out_size, lzma_action action lzma_attribute((unused)))
+		size_t out_size,
+		lzma_action action lzma_attribute((__unused__)))
 {
 	// Position where to start calculating CRC32. The idea is that we
 	// need to call lzma_crc32() only once per call to index_encode().
diff --git a/src/liblzma/delta/delta_encoder.c b/src/liblzma/delta/delta_encoder.c
index ea1cc2cb..15c7951e 100644
--- a/src/liblzma/delta/delta_encoder.c
+++ b/src/liblzma/delta/delta_encoder.c
@@ -85,7 +85,7 @@ delta_encode(lzma_coder *coder, lzma_allocator *allocator,
 
 static lzma_ret
 delta_encoder_update(lzma_coder *coder, lzma_allocator *allocator,
-		const lzma_filter *filters_null lzma_attribute((unused)),
+		const lzma_filter *filters_null lzma_attribute((__unused__)),
 		const lzma_filter *reversed_filters)
 {
 	// Delta doesn't and will never support changing the options in
diff --git a/src/liblzma/lz/lz_decoder.c b/src/liblzma/lz/lz_decoder.c
index 2c573551..d74085cf 100644
--- a/src/liblzma/lz/lz_decoder.c
+++ b/src/liblzma/lz/lz_decoder.c
@@ -126,7 +126,7 @@ decode_buffer(lzma_coder *coder,
 
 static lzma_ret
 lz_decode(lzma_coder *coder,
-		lzma_allocator *allocator lzma_attribute((unused)),
+		lzma_allocator *allocator lzma_attribute((__unused__)),
 		const uint8_t *restrict in, size_t *restrict in_pos,
 		size_t in_size, uint8_t *restrict out,
 		size_t *restrict out_pos, size_t out_size,
diff --git a/src/liblzma/lz/lz_encoder.c b/src/liblzma/lz/lz_encoder.c
index 273f577b..e2406965 100644
--- a/src/liblzma/lz/lz_encoder.c
+++ b/src/liblzma/lz/lz_encoder.c
@@ -480,7 +480,7 @@ lz_encoder_end(lzma_coder *coder, lzma_allocator *allocator)
 
 static lzma_ret
 lz_encoder_update(lzma_coder *coder, lzma_allocator *allocator,
-		const lzma_filter *filters_null lzma_attribute((unused)),
+		const lzma_filter *filters_null lzma_attribute((__unused__)),
 		const lzma_filter *reversed_filters)
 {
 	if (coder->lz.options_update == NULL)
diff --git a/src/liblzma/simple/arm.c b/src/liblzma/simple/arm.c
index 8fcf6437..a84702ac 100644
--- a/src/liblzma/simple/arm.c
+++ b/src/liblzma/simple/arm.c
@@ -15,7 +15,7 @@
 
 
 static size_t
-arm_code(lzma_simple *simple lzma_attribute((unused)),
+arm_code(lzma_simple *simple lzma_attribute((__unused__)),
 		uint32_t now_pos, bool is_encoder,
 		uint8_t *buffer, size_t size)
 {
diff --git a/src/liblzma/simple/armthumb.c b/src/liblzma/simple/armthumb.c
index eb6a69d1..4b49175f 100644
--- a/src/liblzma/simple/armthumb.c
+++ b/src/liblzma/simple/armthumb.c
@@ -15,7 +15,7 @@
 
 
 static size_t
-armthumb_code(lzma_simple *simple lzma_attribute((unused)),
+armthumb_code(lzma_simple *simple lzma_attribute((__unused__)),
 		uint32_t now_pos, bool is_encoder,
 		uint8_t *buffer, size_t size)
 {
diff --git a/src/liblzma/simple/ia64.c b/src/liblzma/simple/ia64.c
index fd263d4a..ce3692b9 100644
--- a/src/liblzma/simple/ia64.c
+++ b/src/liblzma/simple/ia64.c
@@ -15,7 +15,7 @@
 
 
 static size_t
-ia64_code(lzma_simple *simple lzma_attribute((unused)),
+ia64_code(lzma_simple *simple lzma_attribute((__unused__)),
 		uint32_t now_pos, bool is_encoder,
 		uint8_t *buffer, size_t size)
 {
diff --git a/src/liblzma/simple/powerpc.c b/src/liblzma/simple/powerpc.c
index aaa14f22..6f835117 100644
--- a/src/liblzma/simple/powerpc.c
+++ b/src/liblzma/simple/powerpc.c
@@ -15,7 +15,7 @@
 
 
 static size_t
-powerpc_code(lzma_simple *simple lzma_attribute((unused)),
+powerpc_code(lzma_simple *simple lzma_attribute((__unused__)),
 		uint32_t now_pos, bool is_encoder,
 		uint8_t *buffer, size_t size)
 {
diff --git a/src/liblzma/simple/simple_coder.c b/src/liblzma/simple/simple_coder.c
index 06db86ec..37de7fa1 100644
--- a/src/liblzma/simple/simple_coder.c
+++ b/src/liblzma/simple/simple_coder.c
@@ -212,7 +212,7 @@ simple_coder_end(lzma_coder *coder, lzma_allocator *allocator)
 
 static lzma_ret
 simple_coder_update(lzma_coder *coder, lzma_allocator *allocator,
-		const lzma_filter *filters_null lzma_attribute((unused)),
+		const lzma_filter *filters_null lzma_attribute((__unused__)),
 		const lzma_filter *reversed_filters)
 {
 	// No update support, just call the next filter in the chain.
diff --git a/src/liblzma/simple/sparc.c b/src/liblzma/simple/sparc.c
index 808a59aa..8270d6ab 100644
--- a/src/liblzma/simple/sparc.c
+++ b/src/liblzma/simple/sparc.c
@@ -15,7 +15,7 @@
 
 
 static size_t
-sparc_code(lzma_simple *simple lzma_attribute((unused)),
+sparc_code(lzma_simple *simple lzma_attribute((__unused__)),
 		uint32_t now_pos, bool is_encoder,
 		uint8_t *buffer, size_t size)
 {
diff --git a/src/lzmainfo/lzmainfo.c b/src/lzmainfo/lzmainfo.c
index 3100dc63..b0ccdfb4 100644
--- a/src/lzmainfo/lzmainfo.c
+++ b/src/lzmainfo/lzmainfo.c
@@ -26,7 +26,7 @@
 #endif
 
 
-static void lzma_attribute((noreturn))
+static void lzma_attribute((__noreturn__))
 help(void)
 {
 	printf(
@@ -45,7 +45,7 @@ _("Usage: %s [--help] [--version] [FILE]...\n"
 }
 
 
-static void lzma_attribute((noreturn))
+static void lzma_attribute((__noreturn__))
 version(void)
 {
 	puts("lzmainfo (" PACKAGE_NAME ") " LZMA_VERSION_STRING);
diff --git a/src/xz/coder.c b/src/xz/coder.c
index 5182dddc..b123ec5b 100644
--- a/src/xz/coder.c
+++ b/src/xz/coder.c
@@ -102,7 +102,7 @@ coder_add_filter(lzma_vli id, void *options)
 }
 
 
-static void lzma_attribute((noreturn))
+static void lzma_attribute((__noreturn__))
 memlimit_too_small(uint64_t memory_usage)
 {
 	message(V_ERROR, _("Memory usage limit is too low for the given "
diff --git a/src/xz/hardware.h b/src/xz/hardware.h
index bed952b0..ad526f26 100644
--- a/src/xz/hardware.h
+++ b/src/xz/hardware.h
@@ -35,4 +35,4 @@ extern void hardware_memlimit_set(uint64_t new_memlimit,
 extern uint64_t hardware_memlimit_get(enum operation_mode mode);
 
 /// Display the amount of RAM and memory usage limits and exit.
-extern void hardware_memlimit_show(void) lzma_attribute((noreturn));
+extern void hardware_memlimit_show(void) lzma_attribute((__noreturn__));
diff --git a/src/xz/message.c b/src/xz/message.c
index 38cce4a1..e128cf57 100644
--- a/src/xz/message.c
+++ b/src/xz/message.c
@@ -94,7 +94,7 @@ static volatile sig_atomic_t progress_needs_updating = false;
 
 /// Signal handler for SIGALRM
 static void
-progress_signal_handler(int sig lzma_attribute((unused)))
+progress_signal_handler(int sig lzma_attribute((__unused__)))
 {
 	progress_needs_updating = true;
 	return;
diff --git a/src/xz/message.h b/src/xz/message.h
index e3fca3cc..74599bd9 100644
--- a/src/xz/message.h
+++ b/src/xz/message.h
@@ -45,7 +45,7 @@ extern enum message_verbosity message_verbosity_get(void);
 ///
 /// This doesn't touch the exit status.
 extern void message(enum message_verbosity verbosity, const char *fmt, ...)
-		lzma_attribute((format(printf, 2, 3)));
+		lzma_attribute((__format__(__printf__, 2, 3)));
 
 
 /// \brief      Prints a warning and possibly sets exit status
@@ -53,7 +53,7 @@ extern void message(enum message_verbosity verbosity, const char *fmt, ...)
 /// The message is printed only if verbosity level is at least V_WARNING.
 /// The exit status is set to WARNING unless it was already at ERROR.
 extern void message_warning(const char *fmt, ...)
-		lzma_attribute((format(printf, 1, 2)));
+		lzma_attribute((__format__(__printf__, 1, 2)));
 
 
 /// \brief      Prints an error message and sets exit status
@@ -61,25 +61,25 @@ extern void message_warning(const char *fmt, ...)
 /// The message is printed only if verbosity level is at least V_ERROR.
 /// The exit status is set to ERROR.
 extern void message_error(const char *fmt, ...)
-		lzma_attribute((format(printf, 1, 2)));
+		lzma_attribute((__format__(__printf__, 1, 2)));
 
 
 /// \brief      Prints an error message and exits with EXIT_ERROR
 ///
 /// The message is printed only if verbosity level is at least V_ERROR.
 extern void message_fatal(const char *fmt, ...)
-		lzma_attribute((format(printf, 1, 2)))
-		lzma_attribute((noreturn));
+		lzma_attribute((__format__(__printf__, 1, 2)))
+		lzma_attribute((__noreturn__));
 
 
 /// Print an error message that an internal error occurred and exit with
 /// EXIT_ERROR.
-extern void message_bug(void) lzma_attribute((noreturn));
+extern void message_bug(void) lzma_attribute((__noreturn__));
 
 
 /// Print a message that establishing signal handlers failed, and exit with
 /// exit status ERROR.
-extern void message_signal_handler(void) lzma_attribute((noreturn));
+extern void message_signal_handler(void) lzma_attribute((__noreturn__));
 
 
 /// Convert lzma_ret to a string.
@@ -116,11 +116,11 @@ extern void message_try_help(void);
 
 
 /// Prints the version number to stdout and exits with exit status SUCCESS.
-extern void message_version(void) lzma_attribute((noreturn));
+extern void message_version(void) lzma_attribute((__noreturn__));
 
 
 /// Print the help message.
-extern void message_help(bool long_help) lzma_attribute((noreturn));
+extern void message_help(bool long_help) lzma_attribute((__noreturn__));
 
 
 /// \brief      Set the total number of files to be processed
diff --git a/src/xz/options.c b/src/xz/options.c
index 379a2e46..f21a0ba5 100644
--- a/src/xz/options.c
+++ b/src/xz/options.c
@@ -150,7 +150,7 @@ enum {
 
 static void
 set_delta(void *options, uint32_t key, uint64_t value,
-		const char *valuestr lzma_attribute((unused)))
+		const char *valuestr lzma_attribute((__unused__)))
 {
 	lzma_options_delta *opt = options;
 	switch (key) {
@@ -194,7 +194,7 @@ enum {
 
 static void
 set_bcj(void *options, uint32_t key, uint64_t value,
-		const char *valuestr lzma_attribute((unused)))
+		const char *valuestr lzma_attribute((__unused__)))
 {
 	lzma_options_bcj *opt = options;
 	switch (key) {
@@ -241,7 +241,7 @@ enum {
 };
 
 
-static void lzma_attribute((noreturn))
+static void lzma_attribute((__noreturn__))
 error_lzma_preset(const char *valuestr)
 {
 	message_fatal(_("Unsupported LZMA1/LZMA2 preset: %s"), valuestr);
diff --git a/src/xz/signals.c b/src/xz/signals.c
index 4d6a9da3..de213644 100644
--- a/src/xz/signals.c
+++ b/src/xz/signals.c
@@ -179,7 +179,7 @@ signals_exit(void)
 // console window.
 
 static BOOL WINAPI
-signal_handler(DWORD type lzma_attribute((unused)))
+signal_handler(DWORD type lzma_attribute((__unused__)))
 {
 	// Since we don't get a signal number which we could raise() at
 	// signals_exit() like on POSIX, just set the exit status to
diff --git a/src/xz/util.h b/src/xz/util.h
index 4b2d3e2f..a2516bf9 100644
--- a/src/xz/util.h
+++ b/src/xz/util.h
@@ -20,11 +20,11 @@
 
 /// \brief      Safe realloc() that never returns NULL
 extern void *xrealloc(void *ptr, size_t size)
-		lzma_attribute((malloc)) lzma_attr_alloc_size(2);
+		lzma_attribute((__malloc__)) lzma_attr_alloc_size(2);
 
 
 /// \brief      Safe strdup() that never returns NULL
-extern char *xstrdup(const char *src) lzma_attribute((malloc));
+extern char *xstrdup(const char *src) lzma_attribute((__malloc__));
 
 
 /// \brief      Fancy version of strtoull()
@@ -102,7 +102,7 @@ extern const char *uint64_to_nicestr(uint64_t value,
 /// A maximum of *left bytes is written starting from *pos. *pos and *left
 /// are updated accordingly.
 extern void my_snprintf(char **pos, size_t *left, const char *fmt, ...)
-		lzma_attribute((format(printf, 3, 4)));
+		lzma_attribute((__format__(__printf__, 3, 4)));
 
 
 /// \brief      Check if filename is empty and print an error message
diff --git a/src/xzdec/xzdec.c b/src/xzdec/xzdec.c
index fd015076..b7830db4 100644
--- a/src/xzdec/xzdec.c
+++ b/src/xzdec/xzdec.c
@@ -40,7 +40,7 @@
 static unsigned int display_errors = 2;
 
 
-static void lzma_attribute((format(printf, 1, 2)))
+static void lzma_attribute((__format__(__printf__, 1, 2)))
 my_errorf(const char *fmt, ...)
 {
 	va_list ap;
@@ -57,7 +57,7 @@ my_errorf(const char *fmt, ...)
 }
 
 
-static void lzma_attribute((noreturn))
+static void lzma_attribute((__noreturn__))
 help(void)
 {
 	printf(
@@ -81,7 +81,7 @@ PACKAGE_NAME " home page: <" PACKAGE_URL ">\n", progname);
 }
 
 
-static void lzma_attribute((noreturn))
+static void lzma_attribute((__noreturn__))
 version(void)
 {
 	printf(TOOL_FORMAT "dec (" PACKAGE_NAME ") " LZMA_VERSION_STRING "\n"