Rewrite RGBLINK entirely

The goal was to improve readability, but along the way a few things were
gained.
- Sorted sym and map files
- Infrastructure for supporting multiple .o versions
- Valgrind-proof, as far as my testing goes anyways
- Improved verbosity messages
- Added error checking
- Performance improvements, see end of commit message

The readability improvement was spurred while trying to make sense of the
old code while trying to implement features such as sorted sym and map
files.
I also did my best to remove hardcoded logic, such that modifications
should be doable; for example, "RAM loading" sections, which are linked
against a different location than the one they're stored at.

Some work remains to be done, see the "TODO:" and "FIXME:" comments.
Further, while regression tests pass, this new linker should be tested on
different codebases (ideally while instrumented with `make develop` and
under valgrind).
The few errors spotted in the man pages (alignment) need to be corrected.
Finally, documentation comments need to be written, I have written a lot of
them but not all.

This also provides a significant performance boost (benchmarked with a
51994-symbol project):

Current master RGBLINK:
2.02user 0.03system 0:02.06elapsed 99%CPU (0avgtext+0avgdata 84336maxresident)k
0inputs+11584outputs (0major+20729minor)pagefaults 0swaps

Rewritten RGBLINK:
0.19user 0.06system 0:00.63elapsed 40%CPU (0avgtext+0avgdata 32460maxresident)k
23784inputs+11576outputs (0major+7672minor)pagefaults 0swaps

src/asm/output.c

@@ -96,21 +96,21 @@ void out_PopSection(void)
 static uint32_t getmaxsectionsize(uint32_t secttype, char *sectname)
 {
 	switch (secttype) {
-	case SECT_ROM0:
+	case SECTTYPE_ROM0:
 		return 0x8000; /* If ROMX sections not used */
-	case SECT_ROMX:
+	case SECTTYPE_ROMX:
 		return 0x4000;
-	case SECT_VRAM:
+	case SECTTYPE_VRAM:
 		return 0x2000;
-	case SECT_SRAM:
+	case SECTTYPE_SRAM:
 		return 0x2000;
-	case SECT_WRAM0:
+	case SECTTYPE_WRAM0:
 		return 0x2000; /* If WRAMX sections not used */
-	case SECT_WRAMX:
+	case SECTTYPE_WRAMX:
 		return 0x1000;
-	case SECT_OAM:
+	case SECTTYPE_OAM:
 		return 0xA0;
-	case SECT_HRAM:
+	case SECTTYPE_HRAM:
 		return 0x7F;
 	default:
 		break;
@@ -241,7 +241,7 @@ static void writesection(struct Section *pSect, FILE *f)
 	fputlong(pSect->nBank, f);
 	fputlong(pSect->nAlign, f);
 
-	if ((pSect->nType == SECT_ROM0) || (pSect->nType == SECT_ROMX)) {
+	if (sect_HasData(pSect->nType)) {
 		struct Patch *pPatch;
 
 		fwrite(pSect->tData, 1, pSect->nPC, f);
@@ -265,23 +265,23 @@ static void writesymbol(struct sSymbol *pSym, FILE *f)
 	int32_t sectid;
 
 	if (!(pSym->nType & SYMF_DEFINED)) {
-		type = SYM_IMPORT;
+		type = SYMTYPE_IMPORT;
 	} else if (pSym->nType & SYMF_EXPORT) {
-		type = SYM_EXPORT;
+		type = SYMTYPE_EXPORT;
 	} else {
-		type = SYM_LOCAL;
+		type = SYMTYPE_LOCAL;
 	}
 
 	switch (type) {
-	case SYM_LOCAL:
+	case SYMTYPE_LOCAL:
 		offset = pSym->nValue;
 		sectid = getsectid(pSym->pSection);
 		break;
-	case SYM_IMPORT:
+	case SYMTYPE_IMPORT:
 		offset = 0;
 		sectid = -1;
 		break;
-	case SYM_EXPORT:
+	case SYMTYPE_EXPORT:
 		offset = pSym->nValue;
 		if (pSym->nType & SYMF_CONST)
 			sectid = -1;
@@ -293,7 +293,7 @@ static void writesymbol(struct sSymbol *pSym, FILE *f)
 	fputstring(pSym->tzName, f);
 	fputc(type, f);
 
-	if (type != SYM_IMPORT) {
+	if (type != SYMTYPE_IMPORT) {
 		fputstring(pSym->tzFileName, f);
 		fputlong(pSym->nFileLine, f);
 
@@ -496,8 +496,7 @@ static void checksection(void)
 static void checkcodesection(void)
 {
 	checksection();
-	if (pCurrentSection->nType != SECT_ROM0 &&
-	    pCurrentSection->nType != SECT_ROMX) {
+	if (!sect_HasData(pCurrentSection->nType)) {
 		fatalerror("Section '%s' cannot contain code or data (not ROM0 or ROMX)",
 			   pCurrentSection->pzName);
 	} else if (nUnionDepth > 0) {
@@ -570,8 +569,7 @@ void out_WriteObject(void)
 	if (f == NULL)
 		fatalerror("Couldn't write file '%s'\n", tzObjectname);
 
-	fwrite(RGBDS_OBJECT_VERSION_STRING, 1,
-	       strlen(RGBDS_OBJECT_VERSION_STRING), f);
+	fprintf(f, RGBDS_OBJECT_VERSION_STRING, RGBDS_OBJECT_VERSION_NUMBER);
 
 	fputlong(countsymbols(), f);
 	fputlong(countsections(), f);
@@ -647,7 +645,7 @@ struct Section *out_FindSection(char *pzName, uint32_t secttype, int32_t org,
 	pSect->charmap = NULL;
 
 	/* It is only needed to allocate memory for ROM sections. */
-	if (secttype == SECT_ROM0 || secttype == SECT_ROMX) {
+	if (sect_HasData(secttype)) {
 		uint32_t sectsize;
 
 		sectsize = getmaxsectionsize(secttype, pzName);
@@ -743,8 +741,7 @@ void out_Skip(int32_t skip)
 {
 	checksection();
 	checksectionoverflow(skip);
-	if (!((pCurrentSection->nType == SECT_ROM0)
-		|| (pCurrentSection->nType == SECT_ROMX))) {
+	if (!sect_HasData(pCurrentSection->nType)) {
 		pCurrentSection->nPC += skip;
 		nPC += skip;
 		pPCSymbol->nValue += skip;
@@ -779,7 +776,7 @@ void out_RelByte(struct Expression *expr)
 	checksectionoverflow(1);
 	if (rpn_isReloc(expr)) {
 		pCurrentSection->tData[nPC] = 0;
-		createpatch(PATCH_BYTE, expr);
+		createpatch(PATCHTYPE_BYTE, expr);
 		pCurrentSection->nPC += 1;
 		nPC += 1;
 		pPCSymbol->nValue += 1;
@@ -815,7 +812,7 @@ void out_RelWord(struct Expression *expr)
 	if (rpn_isReloc(expr)) {
 		pCurrentSection->tData[nPC] = 0;
 		pCurrentSection->tData[nPC + 1] = 0;
-		createpatch(PATCH_WORD_L, expr);
+		createpatch(PATCHTYPE_WORD, expr);
 		pCurrentSection->nPC += 2;
 		nPC += 2;
 		pPCSymbol->nValue += 2;
@@ -854,7 +851,7 @@ void out_RelLong(struct Expression *expr)
 		pCurrentSection->tData[nPC + 1] = 0;
 		pCurrentSection->tData[nPC + 2] = 0;
 		pCurrentSection->tData[nPC + 3] = 0;
-		createpatch(PATCH_LONG_L, expr);
+		createpatch(PATCHTYPE_LONG, expr);
 		pCurrentSection->nPC += 4;
 		nPC += 4;
 		pPCSymbol->nValue += 4;
@@ -875,7 +872,7 @@ void out_PCRelByte(struct Expression *expr)
 
 	/* Always let the linker calculate the offset. */
 	pCurrentSection->tData[nPC] = 0;
-	createpatch(PATCH_BYTE_JR, expr);
+	createpatch(PATCHTYPE_JR, expr);
 	pCurrentSection->nPC += 1;
 	nPC += 1;
 	pPCSymbol->nValue += 1;