Tweaked the GNUmakefile to (more or less) work with gcc.

Fixed block introspection for the new (Apple-compatible) ABI.

GNUmakefile

@@ -83,12 +83,13 @@ libobjc_LIB_DIRS += -L toydispatch/obj
 libobjc_CFLAGS +=  -O3
 
 ifneq ($(findstring gcc, $(CC)),)
-libobjc_CFLAGS += -fgnu89-inline 
+  # Hack to get the __sync_* GCC builtins to work with GCC
+  ifeq ($(GNUSTEP_TARGET_CPU), ix86)
+    libobjc_CFLAGS += -march=i586
+  endif
 endif
 
 ifeq ($(GNUSTEP_TARGET_OS), mingw32)
-# Hack to get the __sync_* GCC builtins to work on Windows
-libobjc_CFLAGS += -march=i586
 # Hack to get mingw to provide declaration for strdup (since it is non-standard)
 libobjc_CPPFLAGS += -U__STRICT_ANSI__
 endif

blocks_runtime.m

@@ -42,6 +42,7 @@ enum {
 	BLOCK_HAS_CTOR         = (1 << 26), // helpers have C++ code
 	BLOCK_IS_GLOBAL        = (1 << 28),
 	BLOCK_HAS_DESCRIPTOR   = (1 << 29), // interim until complete world build is accomplished
+	BLOCK_HAS_SIGNATURE    = (1 << 30)
 };
 
 // _Block_object_assign() and _Block_object_dispose() flag helpers.
@@ -55,20 +56,50 @@ enum {
 	BLOCK_BYREF_CALLER	  = 128, // called from byref copy/dispose helpers
 };
 
+/**
+ * Block descriptor that contains copy and dispose operations.
+ */
+struct block_descriptor_copydispose
+{
+	unsigned long int reserved;
+	/** Size of the block. */
+	unsigned long int size;
+	/**
+	 * Copy function, generated by the compiler to help copy the block if it
+	 * contains nontrivial copy operations.
+	 */
+	void (*copy_helper)(void *dst, void *src);
+	/**
+	 * Dispose function, generated by the compiler to help copy the block if it
+	 * contains nontrivial destructors.
+	 */
+	void (*dispose_helper)(void *src); 
+	/**
+	 * Objective-C type encoding of the block.
+	 */
+	const char *encoding;
+};
+/**
+ * Block descriptor that does not contain copy and dispose helper functions.
+ */
+struct block_descriptor
+{
+	unsigned long int reserved;
+	/** Size of the block. */
+	unsigned long int size;
+	/**
+	 * Objective-C type encoding of the block.
+	 */
+	const char *encoding;
+};
+
 // Helper structure
 struct psy_block_literal {
 	void *isa; // initialized to &_NSConcreteStackBlock or &_NSConcreteGlobalBlock
 	int flags;
 	int reserved;
 	void (*invoke)(void *, ...);
-	struct {
-		unsigned long int reserved;	// NULL
-		unsigned long int size;  // sizeof(struct Block_literal_1)
-		// optional helper functions
-		void (*copy_helper)(void *dst, void *src);
-		void (*dispose_helper)(void *src); 
-	} *descriptor;
-	const char *types;
+	struct block_descriptor_copydispose *descriptor;
 };
 
 // Helper structure
@@ -81,6 +112,21 @@ struct psy_block_byref_obj {
 	void (*byref_dispose)(struct psy_block_byref_obj *);
 };
 
+const char *block_getType_np(void *b)
+{
+	struct psy_block_literal *block = b;
+	if ((NULL == block) || !(block->flags & BLOCK_HAS_SIGNATURE))
+	{
+		return NULL;
+	}
+	if (!(block->flags & BLOCK_HAS_COPY_DISPOSE))
+	{
+		return ((struct block_descriptor*)block->descriptor)->encoding;
+	}
+	return block->descriptor->encoding;
+}
+
+
 /* Certain field types require runtime assistance when being copied to the
  * heap.  The following function is used to copy fields of types: blocks,
  * pointers to byref structures, and objects (including
@@ -240,9 +286,3 @@ void _Block_release(void *src)
 		}
 	}
 }
-
-const char *_Block_get_types(void *blk)
-{
-	struct psy_block_literal *block = blk;
-	return block->types;
-}

objc/blocks_runtime.h

@@ -11,7 +11,7 @@
 
 BLOCKS_EXPORT void *_Block_copy(void *);
 BLOCKS_EXPORT void _Block_release(void *);
-BLOCKS_EXPORT const char *_Block_get_types(void*) OBJC_NONPORTABLE;
+BLOCKS_EXPORT const char *block_getType_np(void *b) OBJC_NONPORTABLE;
 
 #define Block_copy(x) ((__typeof(x))_Block_copy((void *)(x)))
 #define Block_release(x) _Block_release((void *)(x))

toydispatch/GNUmakefile

@@ -15,11 +15,16 @@ toydispatch_LIBRARIES_DEPEND_UPON += -lpthread
 
 toydispatch_CFLAGS += -Werror -std=c99
 
+ifneq ($(findstring gcc, $(CC)),)
+  # Hack to get the __sync_* GCC builtins to work with GCC
+  ifeq ($(GNUSTEP_TARGET_CPU), ix86)
+    toydispatch_CFLAGS += -march=i586
+  endif
+endif
+
 ifeq ($(GNUSTEP_TARGET_OS), mingw32)
-# Hack to get the __sync_* GCC builtins to work on Windows
-toydispatch_CFLAGS += -march=i586
-# Hack to get mingw to provide declaration for strdup (since it is non-standard)
-toydispatch_CPPFLAGS += -U__STRICT_ANSI__
+  # Hack to get mingw to provide declaration for strdup (since it is non-standard)
+  toydispatch_CPPFLAGS += -U__STRICT_ANSI__
 endif
 
 include $(GNUSTEP_MAKEFILES)/library.make