Undefine __BLOCKS__ before the cups.h import as some versions of this

header file expect unconditional that libdispatch is present when that
variable is defined.
Remove duplicated -allocWithZone: methods.

ChangeLog

@@ -1,3 +1,13 @@
+2017-12-28 Fred Kiefer <FredKiefer@gmx.de>
+
+	* Printing/GSCUPS/GSCUPSPrinter.m,
+	* Printing/GSCUPS/GSCUPSPrintInfo.m,
+	* Printing/GSCUPS/GSCUPSPrintOperation.m: Undefine __BLOCKS__
+	before the cups.h import as some versions of this header file
+	expect unconditional that libdispatch is present when that
+	variable is defined.
+	Remove duplicated -allocWithZone: methods.
+
 2017-12-27 Richard Frith-Macdonald <rfm@gnu.org>
 
 	* Source/NSGraphicsContext.m:  When using clang and the gnustep

Printing/GSCUPS/GSCUPSPrintInfo.m

@@ -32,6 +32,10 @@
 #import "AppKit/NSPrinter.h"
 #import "GSCUPSPrintInfo.h"
 #import "GSCUPSPrinter.h"
+// There are broken versions of cups.h where __BLOCKS__ requires
+// libdispatch to be present. This has long been fixed in CUPS,
+// but the file is still in CentOS 7. 
+#undef __BLOCKS__
 #include <cups/cups.h>
 
 
@@ -45,18 +49,12 @@
   if (self == [GSCUPSPrintInfo class])
     {
       // Initial version
-      [self setVersion:1];
+      [self setVersion: 1];
     }
 }
 
 
-+ (id) allocWithZone: (NSZone*)zone
-{
-  return NSAllocateObject(self, 0, zone);
-}
-
-
-+(NSPrinter*) defaultPrinter
++ (NSPrinter*) defaultPrinter
 {
   NSString *defaultName;
   int numDests;

Printing/GSCUPS/GSCUPSPrintOperation.m

@@ -41,19 +41,12 @@
 #import <AppKit/NSPrintOperation.h>
 #import "GSGuiPrivate.h"
 #import "GSCUPSPrintOperation.h"
+#undef __BLOCKS__
 #include <cups/cups.h>
 
 
 //A subclass of GSPrintOperation, NOT NSPrintOperation.
 @implementation GSCUPSPrintOperation
-//
-// Class methods
-//
-+ (id) allocWithZone: (NSZone*)zone
-{
-  return NSAllocateObject(self, 0, zone);
-}
-
 
 - (id)initWithView:(NSView *)aView
          printInfo:(NSPrintInfo *)aPrintInfo

Printing/GSCUPS/GSCUPSPrinter.m

@@ -48,6 +48,7 @@
 #import "GNUstepGUI/GSPrinting.h"
 #import "GSCUPSPrinter.h"
 
+#undef __BLOCKS__
 #include <cups/cups.h>
 #include <cups/ppd.h>
 
@@ -68,12 +69,6 @@ NSString *GSCUPSDummyPrinterName = @"GSCUPSDummyPrinter";
     }
 }
 
-
-+(id) allocWithZone: (NSZone*) zone
-{
-  return NSAllocateObject(self, 0, zone);
-}
-
 //
 // Finding an NSPrinter 
 //