Index: configure.ac
==================================================================
--- configure.ac
+++ configure.ac
@@ -57,14 +57,10 @@
 
 AC_CHECK_LIB(dl, dlopen, LIBS="$LIBS -ldl")
 
 AC_CHECK_HEADER(objc/runtime.h,
 	[AC_DEFINE(HAVE_OBJC_RUNTIME_H, 1, [Whether we have objc/runtime.h])])
-AC_CHECK_LIB(objc, sel_get_name,
-	[AC_DEFINE(HAVE_SEL_GET_NAME, 1, [Whether we have sel_get_name])])
-AC_CHECK_LIB(objc, sel_getName,
-	[AC_DEFINE(HAVE_SEL_GETNAME, 1, [Whether we have sel_getName])])
 
 AC_CHECK_FUNC(asprintf, [
 	have_asprintf="yes"
 	AC_DEFINE(HAVE_ASPRINTF, 1, "Whether we have asprintf")], [
 	have_asprintf="no"

Index: src/OFExceptions.h
==================================================================
--- src/OFExceptions.h
+++ src/OFExceptions.h
@@ -111,10 +111,37 @@
  * \return A pointer to the memory which is not part of the object
  */
 - (void*)pointer;
 @end
 
+/**
+ * An OFException indicating that a method or part of it is not implemented.
+ */
+@interface OFNotImplementedException: OFException
+{
+	SEL selector;
+}
+
+/**
+ * \param class The class of the object which caused the exception
+ * \param selector The selector which is not or not fully implemented
+ * \return A new not implemented exception
+ */
++ newWithClass: (Class)class
+   andSelector: (SEL)selector;
+
+/**
+ * Initializes an already allocated not implemented exception.
+ *
+ * \param class The class of the object which caused the exception
+ * \param selector The selector which is not or not fully implemented
+ * \return An initialized not implemented exception
+ */
+- initWithClass: (Class)class
+    andSelector: (SEL)selector;
+@end
+
 /**
  * An OFException indicating the given value is out of range.
  */
 @interface OFOutOfRangeException: OFException {}
 @end

Index: src/OFExceptions.m
==================================================================
--- src/OFExceptions.m
+++ src/OFExceptions.m
@@ -29,24 +29,19 @@
 #define ERRFMT	     "Error code was: %d"
 #define ERRPARAM     err
 #endif
 
 #import <objc/objc-api.h>
-#ifdef HAVE_OBJC_RUNTIME_H
+#ifdef __objc_INCLUDE_GNU
+#define SEL_NAME(x) sel_get_name(x)
+#else
 #import <objc/runtime.h>
+#define SEL_NAME(x) sel_getName(x)
 #endif
 
 #import "OFExceptions.h"
 
-#if defined(HAVE_SEL_GET_NAME)
-#define SEL_NAME(x) sel_get_name(x)
-#elif defined(HAVE_SEL_GETNAME)
-#define SEL_NAME(x) sel_getName(x)
-#else
-#error "You need either sel_get_name() or sel_getName()!"
-#endif
-
 #ifndef HAVE_ASPRINTF
 #import "asprintf.h"
 #endif
 
 @implementation OFException
@@ -151,10 +146,39 @@
 - (void*)pointer
 {
 	return pointer;
 }
 @end
+
+@implementation OFNotImplementedException
++ newWithClass: (Class)class_
+   andSelector: (SEL)selector_
+{
+	return [[self alloc] initWithClass: class_
+			       andSelector: selector_];
+}
+
+- initWithClass: (Class)class_
+    andSelector: (SEL)selector_
+{
+	if ((self = [super initWithClass: class_]))
+		selector = selector_;
+
+	return self;
+}
+
+- (const char*)cString
+{
+	if (string != NULL)
+		return string;
+
+	asprintf(&string, "The method %s of class %s is not or not fully "
+	    "implemented!", SEL_NAME(selector), [class name]);
+
+	return string;
+}
+@end
 
 @implementation OFOutOfRangeException
 - (const char*)cString
 {
 	if (string != NULL)