Port linkerscript parser to Bison (#1266)

Notable side effects:
* Use the standard-conformant MSVC preproc
* Add test for linker script INCLUDE
* Improve wording of placement conflict errors
* Fix errors from not newline-terminated files
* Teach checkdiff about the linker script doc
* Call linker script "commands" "directives" instead

---------

Co-authored-by: Rangi42 <remy.oukaour+rangi42@gmail.com>

src/linkdefs.cpp

@@ -3,60 +3,62 @@
 #include "linkdefs.hpp"
 #include "platform.hpp"
 
+using namespace std::literals;
+
 // The default values are the most lax, as they are used as-is by RGBASM; only RGBLINK has the full info,
 // so RGBASM's job is only to catch unconditional errors earlier.
 struct SectionTypeInfo sectionTypeInfo[SECTTYPE_INVALID] = {
 	AT(SECTTYPE_WRAM0) {
-		.name = "WRAM0",
+		.name = "WRAM0"s,
 		.startAddr = 0xC000,
 		.size = 0x2000, // Patched to 0x1000 if !isWRA0Mode
 		.firstBank = 0,
 		.lastBank = 0,
 	},
 	AT(SECTTYPE_VRAM) {
-		.name = "VRAM",
+		.name = "VRAM"s,
 		.startAddr = 0x8000,
 		.size = 0x2000,
 		.firstBank = 0,
 		.lastBank = 1, // Patched to 0 if isDmgMode
 	},
 	AT(SECTTYPE_ROMX) {
-		.name = "ROMX",
+		.name = "ROMX"s,
 		.startAddr = 0x4000,
 		.size = 0x4000,
 		.firstBank = 1,
 		.lastBank = 65535,
 	},
 	AT(SECTTYPE_ROM0) {
-		.name = "ROM0",
+		.name = "ROM0"s,
 		.startAddr = 0x0000,
 		.size = 0x8000, // Patched to 0x4000 if !is32kMode
 		.firstBank = 0,
 		.lastBank = 0,
 	},
 	AT(SECTTYPE_HRAM) {
-		.name = "HRAM",
+		.name = "HRAM"s,
 		.startAddr = 0xFF80,
 		.size = 0x007F,
 		.firstBank = 0,
 		.lastBank = 0,
 	},
 	AT(SECTTYPE_WRAMX) {
-		.name = "WRAMX",
+		.name = "WRAMX"s,
 		.startAddr = 0xD000,
 		.size = 0x1000,
 		.firstBank = 1,
 		.lastBank = 7,
 	},
 	AT(SECTTYPE_SRAM) {
-		.name = "SRAM",
+		.name = "SRAM"s,
 		.startAddr = 0xA000,
 		.size = 0x2000,
 		.firstBank = 0,
 		.lastBank = 255,
 	},
 	AT(SECTTYPE_OAM) {
-		.name = "OAM",
+		.name = "OAM"s,
 		.startAddr = 0xFE00,
 		.size = 0x00A0,
 		.firstBank = 0,