Index: src/amiga-library.h
==================================================================
--- src/amiga-library.h
+++ src/amiga-library.h
@@ -70,9 +70,11 @@
 	/* Needed only by ObjFW. */
 	int (*_Nonnull vsnprintf)(const char *_Nonnull restrict, size_t,
 	    const char *_Nonnull restrict, va_list);
 	void (*_Nonnull exit)(int);
 	char *_Nullable (*_Nonnull setlocale)(int, const char *_Nullable);
+	int (*_Nonnull _Unwind_Backtrace)(int (*_Nonnull)(void *_Nonnull,
+	    void *_Null_unspecified), void *_Null_unspecified);
 };
 
 extern bool of_init(unsigned int version, struct of_libc *libc, FILE **sF);
 #endif

Index: src/amiga-library.m
==================================================================
--- src/amiga-library.m
+++ src/amiga-library.m
@@ -537,10 +537,16 @@
 char *
 setlocale(int category, const char *locale)
 {
 	return libc.setlocale(category, locale);
 }
+
+int
+_Unwind_Backtrace(int (*callback)(void *, void *), void *data)
+{
+	return libc._Unwind_Backtrace(callback, data);
+}
 
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wpedantic"
 static CONST_APTR functionTable[] = {
 #ifdef OF_MORPHOS

Index: src/runtime/linklib/linklib.m
==================================================================
--- src/runtime/linklib/linklib.m
+++ src/runtime/linklib/linklib.m
@@ -106,15 +106,25 @@
 	if (initialized)
 		return;
 
 	if ((ObjFWRTBase = OpenLibrary(OBJFWRT_AMIGA_LIB,
 	    OBJFWRT_LIB_MINOR)) == NULL) {
+		/*
+		 * The linklib is used by objfw(68k).library as well, so we
+		 * can't have the compiler optimize this to another function,
+		 * hence the use of an unnecessary format specifier.
+		 */
 		fprintf(stderr, "Failed to open %s!\n", OBJFWRT_AMIGA_LIB);
 		abort();
 	}
 
 	if (!glue_objc_init(1, &libc, __sF)) {
+		/*
+		 * The linklib is used by objfw(68k).library as well, so we
+		 * can't have the compiler optimize this to another function,
+		 * hence the use of an unnecessary format specifier.
+		 */
 		fprintf(stderr, "Failed to initialize %s!\n",
 		    OBJFWRT_AMIGA_LIB);
 		abort();
 	}