gcc: Add support for Apple's Block extension

Block objects [1] are a C-level syntactic and runtime feature. They
are similar to standard C functions, but in addition to executable
code they may also contain variable bindings to automatic (stack)
or managed (heap) memory. A block can therefore maintain a set of
state (data) that it can use to impact behavior when executed.

This port is based on Apple's GCC 5646 with some bugfixes from
Apple GCC 5666.3. It has some small differences with the support
in clang, which remains the recommended compiler.

Perhaps the most notable difference is that in GCC that __block
is not actually a keyword, but a macro. There will be workaround
for this issue in a near future. Other issues can be consulted in
the clang documentation [2]

For better compatiblity with Apple's GCC and llvm-gcc some related
fixes and features from Apple have been included. Support for the
non-standard nested functions in GCC is now off by default.

No effort was made to update the ObjC support since FreeBSD doesn't
carry ObjC in the base system, but some of the code crept in and
was more difficult to remove than to adjust.

Reference:
[1]
https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/Blocks/Articles/00_Introduction.html
[2]
http://clang.llvm.org/compatibility.html#block-variable-initialization

Obtained from:	Apple GCC 4.2
MFC after:	3 weeks

1 files changed, 6 insertions, 0 deletions

diff --git a/contrib/gcc/c-objc-common.h b/contrib/gcc/c-objc-common.h
index 49f9ce4..a12704a 100644
--- a/contrib/gcc/c-objc-common.h
+++ b/contrib/gcc/c-objc-common.h
@@ -140,4 +140,10 @@ extern void c_initialize_diagnostics (diagnostic_context *);
 #undef LANG_HOOKS_TREE_INLINING_VAR_MOD_TYPE_P
 #define LANG_HOOKS_TREE_INLINING_VAR_MOD_TYPE_P c_vla_unspec_p
 
+/* APPLE LOCAL begin radar 6353006  */
+#undef LANG_HOOKS_BUILD_GENERIC_BLOCK_STRUCT_TYPE
+#define LANG_HOOKS_BUILD_GENERIC_BLOCK_STRUCT_TYPE \
+c_build_generic_block_struct_type
+/* APPLE LOCAL end radar 6353006  */
+
 #endif /* GCC_C_OBJC_COMMON */