Add missing GS_EXPORT_CLASS annotations.

Headers/Foundation/NSDecimalNumber.h

@@ -119,6 +119,7 @@ extern "C" {
  *  passing an instance as an argument to any [NSDecimalNumber] method ending
  *  with <code>...Behavior:</code>.
  */
+GS_EXPORT_CLASS
 @interface	NSDecimalNumberHandler : NSObject <NSDecimalNumberBehaviors>
 {
 #if	GS_EXPOSE(NSDecimalNumberHandler)
@@ -187,6 +188,7 @@ extern "C" {
  *
  *  <p>Note that instances of <code>NSDecimalNumber</code> are immutable.</p>
  */
+GS_EXPORT_CLASS
 @interface	NSDecimalNumber : NSNumber <NSDecimalNumberBehaviors>
 {
 #if	GS_EXPOSE(NSDecimalNumber)

Headers/Foundation/NSFormatter.h

@@ -62,6 +62,7 @@ typedef NSInteger NSFormattingUnitStyle;
  *  and [NSNumberFormatter].  Others may be implemented for specialized
  *  applications.
  */
+GS_EXPORT_CLASS
 @interface	NSFormatter : NSObject <NSCopying, NSCoding>
 
 /**

Headers/Foundation/NSIndexPath.h

@@ -42,6 +42,7 @@ extern "C" {
  * of arrays.<br />
  * Each instance is a unique shared object.
  */
+GS_EXPORT_CLASS
 @interface	NSIndexPath : NSObject <NSCopying, NSCoding>
 {
 #if	GS_EXPOSE(NSIndexPath)

Headers/Foundation/NSIndexSet.h

@@ -44,6 +44,7 @@ extern "C" {
  * range 0 to NSNotFound-1.<br />
  * Each integer can appear in a collection only once.
  */
+GS_EXPORT_CLASS
 @interface	NSIndexSet : NSObject <NSCopying, NSMutableCopying, NSCoding>
 {
 #if	GS_EXPOSE(NSIndexSet)
@@ -191,6 +192,7 @@ DEFINE_BLOCK_TYPE(GSIndexSetEnumerationBlock, void, NSUInteger, BOOL*);
 @end
 
 
+GS_EXPORT_CLASS
 @interface	NSMutableIndexSet : NSIndexSet
 
 /**

Headers/Foundation/NSSet.h

@@ -164,6 +164,7 @@ GS_EXPORT_CLASS
 /**
  * Utility methods for using a counted set to handle uniquing of objects.
  */
+GS_EXPORT_CLASS
 @interface GS_GENERIC_CLASS(NSCountedSet, ElementT) (GNU_Uniquing)
 /**
  * <p>