Cleanup GCC compiler attributes

Added define 'unused_' for '__attribute__((unused))'. The oldest version
of GCC with online docs (GCC 2.95.3, released in March 16, 2001 [1])
already has support for this attribute, so it doesn't make sense to
check the version.

Renamed 'noreturn' to 'noreturn_' for consistency.

[1] https://gcc.gnu.org/onlinedocs/

Signed-off-by: Antonio Niño Díaz <antonio_nd@outlook.com>

src/asm/globlex.c

@@ -20,6 +20,8 @@
 #include "asm/symbol.h"
 #include "asm/symbol.h"
 
+#include "helpers.h"
+
 #include "asmy.h"
 
 bool oDontExpandStrings;
@@ -219,7 +221,7 @@ uint32_t PutMacroArg(char *src, uint32_t size)
 	return 0;
 }
 
-uint32_t PutUniqueArg(__attribute ((unused)) char *src, uint32_t size)
+uint32_t PutUniqueArg(unused_ char *src, uint32_t size)
 {
 	char *s;
 

src/asm/symbol.c

@@ -25,6 +25,7 @@
 
 #include "extern/err.h"
 
+#include "helpers.h"
 #include "version.h"
 
 struct sSymbol *tHashedSymbols[HASHSIZE];
@@ -62,7 +63,7 @@ void helper_RemoveLeadingZeros(char *string)
 	memmove(string, new_beginning, strlen(new_beginning) + 1);
 }
 
-int32_t Callback_NARG(__attribute__ ((unused)) struct sSymbol *sym)
+int32_t Callback_NARG(unused_ struct sSymbol *sym)
 {
 	uint32_t i = 0;
 
@@ -72,7 +73,7 @@ int32_t Callback_NARG(__attribute__ ((unused)) struct sSymbol *sym)
 	return i;
 }
 
-int32_t Callback__LINE__(struct sSymbol __attribute__((unused)) *sym)
+int32_t Callback__LINE__(unused_ struct sSymbol *sym)
 {
 	return nLineNo;
 }

src/extern/err.c

@@ -33,7 +33,7 @@ void rgbds_vwarnx(const char *fmt, va_list ap)
 	putc('\n', stderr);
 }
 
-noreturn void rgbds_verr(int status, const char *fmt, va_list ap)
+noreturn_ void rgbds_verr(int status, const char *fmt, va_list ap)
 {
 	fprintf(stderr, "error");
 	if (fmt) {
@@ -44,7 +44,7 @@ noreturn void rgbds_verr(int status, const char *fmt, va_list ap)
 	exit(status);
 }
 
-noreturn void rgbds_verrx(int status, const char *fmt, va_list ap)
+noreturn_ void rgbds_verrx(int status, const char *fmt, va_list ap)
 {
 	fprintf(stderr, "error");
 	if (fmt) {
@@ -73,7 +73,7 @@ void rgbds_warnx(const char *fmt, ...)
 	va_end(ap);
 }
 
-noreturn void rgbds_err(int status, const char *fmt, ...)
+noreturn_ void rgbds_err(int status, const char *fmt, ...)
 {
 	va_list ap;
 
@@ -82,7 +82,7 @@ noreturn void rgbds_err(int status, const char *fmt, ...)
 	va_end(ap);
 }
 
-noreturn void rgbds_errx(int status, const char *fmt, ...)
+noreturn_ void rgbds_errx(int status, const char *fmt, ...)
 {
 	va_list ap;
 

src/link/lexer.l

@@ -179,7 +179,7 @@ void script_PrintFileStack(void)
 	fprintf(stderr, "%s(%d)", linkerscript_path, include_line[i]);
 }
 
-noreturn void script_fatalerror(const char *fmt, ...)
+noreturn_ void script_fatalerror(const char *fmt, ...)
 {
 	va_list args;
 	va_start(args, fmt);