Disable GC by default (lots of people moan that it doesn't compile)

Update ANNOUNCE.

ANNOUNCE

@@ -9,15 +9,23 @@ release include:
 - Support for Apple-compatible garbage collection APIs, along with extensions
   to support CoreFoundation-style explicit reference counting in a garbage
   collected environment.  This uses the Boehm garbage collector and is enabled
-  by default.  To build without garbage collection specify the boehm_gc=no
-  option when building.
+  by specifying boehm_gc=yes when building.  This requires version 7.1 or later
+  of libgc.  Code compiled with -fobjc-gc can be mixed with code that
+  implements normal reference counting and with code compiled with
+  -fobjc-gc-only.  The runtime supports both GC and non-GC code when compiled
+  with GC support and will automatically select the correct behavior depending
+  on the loaded code.
+
 - The runtime will now use Boehm GC for several internal data structures, if it
   is built with GC enabled.  This avoids the need for defensive programming
   with respect to thread safety in several places.
+
 - This is the first release to provide a superset of the functionality provided
   by the Mac Objective-C runtime, as shipped with OS X 10.6.
+
 - Full support for Automatic Reference Counting (ARC), compatible with OS X
-  10.7 and iOS 5.
+  10.7 and iOS 5, including support for __weak references.
+
 - The LLVM optimisation passes have been improved and better tested.  Code
   compiled with them now passes the EtoileFoundation test suite.
 

ANNOUNCE.1.5

@@ -9,15 +9,23 @@ release include:
 - Support for Apple-compatible garbage collection APIs, along with extensions
   to support CoreFoundation-style explicit reference counting in a garbage
   collected environment.  This uses the Boehm garbage collector and is enabled
-  by default.  To build without garbage collection specify the boehm_gc=no
-  option when building.
+  by specifying boehm_gc=yes when building.  This requires version 7.1 or later
+  of libgc.  Code compiled with -fobjc-gc can be mixed with code that
+  implements normal reference counting and with code compiled with
+  -fobjc-gc-only.  The runtime supports both GC and non-GC code when compiled
+  with GC support and will automatically select the correct behavior depending
+  on the loaded code.
+
 - The runtime will now use Boehm GC for several internal data structures, if it
   is built with GC enabled.  This avoids the need for defensive programming
   with respect to thread safety in several places.
+
 - This is the first release to provide a superset of the functionality provided
   by the Mac Objective-C runtime, as shipped with OS X 10.6.
+
 - Full support for Automatic Reference Counting (ARC), compatible with OS X
-  10.7 and iOS 5.
+  10.7 and iOS 5, including support for __weak references.
+
 - The LLVM optimisation passes have been improved and better tested.  Code
   compiled with them now passes the EtoileFoundation test suite.
 

GNUmakefile

@@ -86,7 +86,7 @@ ifeq ($(low_memory), yes)
 ${LIBOBJC}_CPPFLAGS += -D__OBJC_LOW_MEMORY__
 endif
 
-ifneq ($(boehm_gc), no)
+ifeq ($(boehm_gc), yes)
 ${LIBOBJC}_C_FILES += gc_boehm.c
 ifneq ($(findstring linux, $(GNUSTEP_TARGET_OS)), linux)
 ${LIBOBJC}_LIBRARIES_DEPEND_UPON += -lgc-threaded -lexecinfo