Revert "As ugly as it looks, only attempt to check for imp_implementa…

…tionWithBlock on the 4.3 SDK and up."

This reverts commit f4efa63.

A2BlockDelegate.m

@@ -32,10 +32,7 @@
 // Forward Declarations
 extern char *a2_property_copyAttributeValue(objc_property_t property, const char *attributeName);
 extern char *property_copyAttributeValue(objc_property_t property, const char *attributeName);
-
-#if __IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_4_3
 extern IMP imp_implementationWithBlock(void *block) __attribute__((weak_import));
-#endif
 
 @interface NSObject ()
 
@@ -267,15 +264,13 @@ static BOOL a2_resolveInstanceMethod(id self, SEL _cmd, SEL selector)
 
 			if (argc == 1)
 			{
-#if __IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_4_3
 				if (imp_implementationWithBlock != NULL)
 				{
 					implementation = imp_implementationWithBlock([[^(NSObject *obj, id block) {
 						[[obj dynamicDelegateForProtocol: protocol] implementMethod: representedSelector withBlock: block];
 					} copy] autorelease]);
 				}
 				else
-#endif
 				{
 					implementation = (IMP) a2_blockPropertySetter;
 				}
@@ -284,15 +279,13 @@ static BOOL a2_resolveInstanceMethod(id self, SEL _cmd, SEL selector)
 			}
 			else
 			{
-#if __IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_4_3
 				if (imp_implementationWithBlock != NULL)
 				{
 					implementation = imp_implementationWithBlock([[^id (NSObject *obj) {
 						return [[obj dynamicDelegateForProtocol: protocol] blockImplementationForMethod: representedSelector];
 					} copy] autorelease]);
 				}
 				else
-#endif
 				{
 					implementation = (IMP) a2_blockPropertyGetter;
 				}