Avoid closing stdin/stdout/stderr standard streams

src/link/object.cpp

@@ -19,6 +19,7 @@
 #include "helpers.hpp"
 #include "linkdefs.hpp"
 #include "platform.hpp"
+#include "util.hpp" // xfclose
 #include "verbosity.hpp"
 #include "version.hpp"
 
@@ -446,7 +447,7 @@ void obj_ReadFile(std::string const &filePath, size_t fileID) {
 	if (!file) {
 		fatal("Failed to open file \"%s\": %s", fileName, strerror(errno));
 	}
-	Defer closeFile{[&] { fclose(file); }};
+	Defer closeFile{[&] { xfclose(file); }};
 
 	// First, check if the object is a RGBDS object, a SDCC one, or neither.
 	// A single `ungetc` is guaranteed to work.

src/link/output.cpp

@@ -218,7 +218,7 @@ static void writeROM() {
 	}
 	Defer closeOutputFile{[&] {
 		if (outputFile) {
-			fclose(outputFile);
+			xfclose(outputFile);
 		}
 	}};
 
@@ -237,7 +237,7 @@ static void writeROM() {
 	}
 	Defer closeOverlayFile{[&] {
 		if (overlayFile) {
-			fclose(overlayFile);
+			xfclose(overlayFile);
 		}
 	}};
 
@@ -556,7 +556,7 @@ static void writeSym() {
 	if (!symFile) {
 		fatal("Failed to open sym file \"%s\": %s", symFileName, strerror(errno));
 	}
-	Defer closeSymFile{[&] { fclose(symFile); }};
+	Defer closeSymFile{[&] { xfclose(symFile); }};
 
 	fputs("; File generated by rgblink\n", symFile);
 
@@ -607,7 +607,7 @@ static void writeMap() {
 	if (!mapFile) {
 		fatal("Failed to open map file \"%s\": %s", mapFileName, strerror(errno));
 	}
-	Defer closeMapFile{[&] { fclose(mapFile); }};
+	Defer closeMapFile{[&] { xfclose(mapFile); }};
 
 	writeMapSummary();