Avoid use of goto in shiftChar

src/asm/lexer.cpp

@@ -862,14 +862,14 @@ static void shiftChar() {
 
 	lexerState->macroArgScanDistance--;
 
-restart:
+	for (;;) {
 		if (!lexerState->expansions.empty()) {
 			// Advance within the current expansion
 			if (Expansion &exp = lexerState->expansions.front(); exp.advance()) {
 				// When advancing would go past an expansion's end,
 				// move up to its parent and try again to advance
 				lexerState->expansions.pop_front();
-			goto restart;
+				continue;
 			}
 		} else {
 			// Advance within the file contents
@@ -879,6 +879,8 @@ restart:
 				lexerState->content.get<BufferedContent>().advance();
 			}
 		}
+		return;
+	}
 }
 
 static int nextChar() {
@@ -2114,7 +2116,7 @@ append:
 		}
 	}
 
-finish:
+finish: // Can't `break` out of a nested `for`-`switch`
 	// Trim right whitespace
 	auto rightPos = std::find_if_not(str.rbegin(), str.rend(), isWhitespace);
 	str.resize(rightPos.base() - str.begin());