Index: src/Makefile
==================================================================
--- src/Makefile
+++ src/Makefile
@@ -7,11 +7,10 @@
 
 SRCS = OFApplication.m		\
        OFArray.m		\
        OFAutoreleasePool.m	\
        OFConstString.m		\
-       ${OFBLOCK_M}		\
        OFDataArray.m		\
        OFDictionary.m		\
        OFExceptions.m		\
        OFFile.m			\
        OFHash.m			\
@@ -41,19 +40,21 @@
        OFXMLElementBuilder.m	\
        OFXMLParser.m		\
        unicode.m
 
 INCLUDES := ${SRCS:.m=.h}	\
+	    OFBlock.h		\
 	    OFCollection.h	\
 	    ObjFW.h		\
 	    asprintf.h		\
 	    ${ATOMIC_H}		\
 	    macros.h		\
 	    objfw-defs.h	\
 	    ${THREADING_H}
 
-SRCS += ${ASPRINTF_M} 		\
+SRCS += ${OFBLOCK_M}		\
+	${ASPRINTF_M} 		\
 	iso_8859_15.m		\
 	windows_1252.m		\
 	${OBJC_PROPERTIES_M}	\
 	${OBJC_SYNC_M}
 

Index: src/OFBlock.h
==================================================================
--- src/OFBlock.h
+++ src/OFBlock.h
@@ -64,7 +64,14 @@
 - copy;
 - (void)release;
 - autorelease;
 @end
 
-extern of_block_literal_t* Block_copy(of_block_literal_t*);
-extern void Block_release(of_block_literal_t*);
+extern void* _Block_copy(const void*);
+extern void _Block_release(const void*);
+
+#ifndef Block_copy
+# define Block_copy(x) ((__typeof__(x))_Block_copy((const void*)(x)))
+#endif
+#ifndef Block_release
+# define Block_release(x) _Block_release((const void*)(x))
+#endif

Index: src/OFBlock.m
==================================================================
--- src/OFBlock.m
+++ src/OFBlock.m
@@ -88,11 +88,11 @@
 	__objc_exec_class(&module);
 }
 /* Emd of ObjC module */
 
 of_block_literal_t*
-Block_copy(of_block_literal_t *block)
+_Block_copy(of_block_literal_t *block)
 {
 	if (block->isa == (Class)&_NSConcreteStackBlock) {
 		of_block_literal_t *copy;
 
 		if ((copy = malloc(block->descriptor->size)) == NULL) {
@@ -115,11 +115,11 @@
 
 	return block;
 }
 
 void
-Block_release(of_block_literal_t *block)
+_Block_release(of_block_literal_t *block)
 {
 	if (block->isa != (Class)&_NSConcreteMallocBlock)
 		return;
 
 	if (--block->reserved == 0) {
@@ -136,11 +136,11 @@
 	flags &= OF_BLOCK_FIELD_IS_BLOCK | OF_BLOCK_FIELD_IS_OBJECT |
 	    OF_BLOCK_FIELD_IS_BYREF;
 
 	switch (flags) {
 	case OF_BLOCK_FIELD_IS_BLOCK:
-		*(of_block_literal_t**)dst = Block_copy(src);
+		*(of_block_literal_t**)dst = _Block_copy(src);
 		break;
 	case OF_BLOCK_FIELD_IS_OBJECT:
 		*(id*)dst = [(id)src retain];
 		break;
 	case OF_BLOCK_FIELD_IS_BYREF:;
@@ -175,11 +175,11 @@
 	flags &= OF_BLOCK_FIELD_IS_BLOCK | OF_BLOCK_FIELD_IS_OBJECT |
 	    OF_BLOCK_FIELD_IS_BYREF;
 
 	switch (flags) {
 	case OF_BLOCK_FIELD_IS_BLOCK:
-		Block_release(obj);
+		_Block_release(obj);
 		break;
 	case OF_BLOCK_FIELD_IS_OBJECT:
 		[(id)obj release];
 		break;
 	case OF_BLOCK_FIELD_IS_BYREF:;
@@ -198,16 +198,16 @@
 static Class autoreleasepool = Nil;
 
 @implementation OFBlock
 - copy
 {
-	return (id)Block_copy((of_block_literal_t*)self);
+	return Block_copy(self);
 }
 
 - (void)release
 {
-	Block_release((of_block_literal_t*)self);
+	Block_release(self);
 }
 
 - autorelease
 {
 	/*