Resolve some TODO comments

- `out_PushSection` should not set `currentSection` to NULL because
  PUSHS, PUSHC, and PUSHO consistently keep the current section,
  charmap, and options, even though the stack has been pushed.

- `Callback__FILE__` does not need to assert that `fileName` is not
  empty because `__FILE__`'s value is quoted, and can safely be empty.

- `YY_FATAL_ERROR` and `YYLMAX` are not needed since the lexer is
  not generated with flex.

include/asm/lexer.h

@@ -53,7 +53,7 @@ static inline void lexer_SetGfxDigits(char const digits[4])
  * `path` is referenced, but not held onto..!
  */
 struct LexerState *lexer_OpenFile(char const *path);
-struct LexerState *lexer_OpenFileView(char *buf, size_t size, uint32_t lineNo);
+struct LexerState *lexer_OpenFileView(char const *path, char *buf, size_t size, uint32_t lineNo);
 void lexer_RestartRept(uint32_t lineNo);
 void lexer_DeleteState(struct LexerState *state);
 void lexer_Init(void);

include/asm/main.h

@@ -26,12 +26,4 @@ extern bool generatedMissingIncludes;
 extern bool failedOnMissingInclude;
 extern bool generatePhonyDeps;
 
-/* TODO: are these really needed? */
-#define YY_FATAL_ERROR fatalerror
-
-#ifdef YYLMAX
-#undef YYLMAX
-#endif
-#define YYLMAX 65536
-
 #endif /* RGBDS_MAIN_H */

include/asm/symbol.h

@@ -45,13 +45,13 @@ struct Symbol {
 		/* If sym_IsNumeric */
 		int32_t value;
 		int32_t (*numCallback)(void);
-		/* For SYM_MACRO */
+		/* For SYM_MACRO and SYM_EQUS; TODO: have separate fields */
 		struct {
 			size_t macroSize;
 			char *macro;
 		};
-		/* For SYM_EQUS, TODO: separate "base" fields from SYM_MACRO */
-		char const *(*strCallback)(void); /* For SYM_EQUS */
+		/* For SYM_EQUS */
+		char const *(*strCallback)(void);
 	};
 
 	uint32_t ID; /* ID of the symbol in the object file (-1 if none) */