diff --git a/ChangeLog b/ChangeLog
index f89a5735d..bfa281c27 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,17 @@
+Tue Nov 10 17:12:45 PST 1998 Manish Singh <yosh@gimp.org>
+
+	* configure.in: use __extension__ for long long on gcc >= 2.8 and
+	egcs, and provide a G_GINT64_CONSTANT wrapper so -ansi -pedantic
+	compiles clean.
+
+	* glib.h: make the endian x86 asm __const__ so the compiler can do
+	better optimizations. Also remove the cc clobber, these shouldn't
+	be changing condition codes. Ditch some redundant casts. Add an
+	optimization for 64-bit endian conversions in x86. Use constant
+	wrapper for the generic method.
+
+	* testglib.c: use constant wrappers for 64-bit constants
+
 1998-11-04  Phil Schwan  <pschwan@cmu.edu>
 
 	* configure.in: Added 'strncasecmp' to the list of functions to be
diff --git a/ChangeLog.pre-2-0 b/ChangeLog.pre-2-0
index f89a5735d..bfa281c27 100644
--- a/ChangeLog.pre-2-0
+++ b/ChangeLog.pre-2-0
@@ -1,3 +1,17 @@
+Tue Nov 10 17:12:45 PST 1998 Manish Singh <yosh@gimp.org>
+
+	* configure.in: use __extension__ for long long on gcc >= 2.8 and
+	egcs, and provide a G_GINT64_CONSTANT wrapper so -ansi -pedantic
+	compiles clean.
+
+	* glib.h: make the endian x86 asm __const__ so the compiler can do
+	better optimizations. Also remove the cc clobber, these shouldn't
+	be changing condition codes. Ditch some redundant casts. Add an
+	optimization for 64-bit endian conversions in x86. Use constant
+	wrapper for the generic method.
+
+	* testglib.c: use constant wrappers for 64-bit constants
+
 1998-11-04  Phil Schwan  <pschwan@cmu.edu>
 
 	* configure.in: Added 'strncasecmp' to the list of functions to be
diff --git a/ChangeLog.pre-2-10 b/ChangeLog.pre-2-10
index f89a5735d..bfa281c27 100644
--- a/ChangeLog.pre-2-10
+++ b/ChangeLog.pre-2-10
@@ -1,3 +1,17 @@
+Tue Nov 10 17:12:45 PST 1998 Manish Singh <yosh@gimp.org>
+
+	* configure.in: use __extension__ for long long on gcc >= 2.8 and
+	egcs, and provide a G_GINT64_CONSTANT wrapper so -ansi -pedantic
+	compiles clean.
+
+	* glib.h: make the endian x86 asm __const__ so the compiler can do
+	better optimizations. Also remove the cc clobber, these shouldn't
+	be changing condition codes. Ditch some redundant casts. Add an
+	optimization for 64-bit endian conversions in x86. Use constant
+	wrapper for the generic method.
+
+	* testglib.c: use constant wrappers for 64-bit constants
+
 1998-11-04  Phil Schwan  <pschwan@cmu.edu>
 
 	* configure.in: Added 'strncasecmp' to the list of functions to be
diff --git a/ChangeLog.pre-2-12 b/ChangeLog.pre-2-12
index f89a5735d..bfa281c27 100644
--- a/ChangeLog.pre-2-12
+++ b/ChangeLog.pre-2-12
@@ -1,3 +1,17 @@
+Tue Nov 10 17:12:45 PST 1998 Manish Singh <yosh@gimp.org>
+
+	* configure.in: use __extension__ for long long on gcc >= 2.8 and
+	egcs, and provide a G_GINT64_CONSTANT wrapper so -ansi -pedantic
+	compiles clean.
+
+	* glib.h: make the endian x86 asm __const__ so the compiler can do
+	better optimizations. Also remove the cc clobber, these shouldn't
+	be changing condition codes. Ditch some redundant casts. Add an
+	optimization for 64-bit endian conversions in x86. Use constant
+	wrapper for the generic method.
+
+	* testglib.c: use constant wrappers for 64-bit constants
+
 1998-11-04  Phil Schwan  <pschwan@cmu.edu>
 
 	* configure.in: Added 'strncasecmp' to the list of functions to be
diff --git a/ChangeLog.pre-2-2 b/ChangeLog.pre-2-2
index f89a5735d..bfa281c27 100644
--- a/ChangeLog.pre-2-2
+++ b/ChangeLog.pre-2-2
@@ -1,3 +1,17 @@
+Tue Nov 10 17:12:45 PST 1998 Manish Singh <yosh@gimp.org>
+
+	* configure.in: use __extension__ for long long on gcc >= 2.8 and
+	egcs, and provide a G_GINT64_CONSTANT wrapper so -ansi -pedantic
+	compiles clean.
+
+	* glib.h: make the endian x86 asm __const__ so the compiler can do
+	better optimizations. Also remove the cc clobber, these shouldn't
+	be changing condition codes. Ditch some redundant casts. Add an
+	optimization for 64-bit endian conversions in x86. Use constant
+	wrapper for the generic method.
+
+	* testglib.c: use constant wrappers for 64-bit constants
+
 1998-11-04  Phil Schwan  <pschwan@cmu.edu>
 
 	* configure.in: Added 'strncasecmp' to the list of functions to be
diff --git a/ChangeLog.pre-2-4 b/ChangeLog.pre-2-4
index f89a5735d..bfa281c27 100644
--- a/ChangeLog.pre-2-4
+++ b/ChangeLog.pre-2-4
@@ -1,3 +1,17 @@
+Tue Nov 10 17:12:45 PST 1998 Manish Singh <yosh@gimp.org>
+
+	* configure.in: use __extension__ for long long on gcc >= 2.8 and
+	egcs, and provide a G_GINT64_CONSTANT wrapper so -ansi -pedantic
+	compiles clean.
+
+	* glib.h: make the endian x86 asm __const__ so the compiler can do
+	better optimizations. Also remove the cc clobber, these shouldn't
+	be changing condition codes. Ditch some redundant casts. Add an
+	optimization for 64-bit endian conversions in x86. Use constant
+	wrapper for the generic method.
+
+	* testglib.c: use constant wrappers for 64-bit constants
+
 1998-11-04  Phil Schwan  <pschwan@cmu.edu>
 
 	* configure.in: Added 'strncasecmp' to the list of functions to be
diff --git a/ChangeLog.pre-2-6 b/ChangeLog.pre-2-6
index f89a5735d..bfa281c27 100644
--- a/ChangeLog.pre-2-6
+++ b/ChangeLog.pre-2-6
@@ -1,3 +1,17 @@
+Tue Nov 10 17:12:45 PST 1998 Manish Singh <yosh@gimp.org>
+
+	* configure.in: use __extension__ for long long on gcc >= 2.8 and
+	egcs, and provide a G_GINT64_CONSTANT wrapper so -ansi -pedantic
+	compiles clean.
+
+	* glib.h: make the endian x86 asm __const__ so the compiler can do
+	better optimizations. Also remove the cc clobber, these shouldn't
+	be changing condition codes. Ditch some redundant casts. Add an
+	optimization for 64-bit endian conversions in x86. Use constant
+	wrapper for the generic method.
+
+	* testglib.c: use constant wrappers for 64-bit constants
+
 1998-11-04  Phil Schwan  <pschwan@cmu.edu>
 
 	* configure.in: Added 'strncasecmp' to the list of functions to be
diff --git a/ChangeLog.pre-2-8 b/ChangeLog.pre-2-8
index f89a5735d..bfa281c27 100644
--- a/ChangeLog.pre-2-8
+++ b/ChangeLog.pre-2-8
@@ -1,3 +1,17 @@
+Tue Nov 10 17:12:45 PST 1998 Manish Singh <yosh@gimp.org>
+
+	* configure.in: use __extension__ for long long on gcc >= 2.8 and
+	egcs, and provide a G_GINT64_CONSTANT wrapper so -ansi -pedantic
+	compiles clean.
+
+	* glib.h: make the endian x86 asm __const__ so the compiler can do
+	better optimizations. Also remove the cc clobber, these shouldn't
+	be changing condition codes. Ditch some redundant casts. Add an
+	optimization for 64-bit endian conversions in x86. Use constant
+	wrapper for the generic method.
+
+	* testglib.c: use constant wrappers for 64-bit constants
+
 1998-11-04  Phil Schwan  <pschwan@cmu.edu>
 
 	* configure.in: Added 'strncasecmp' to the list of functions to be
diff --git a/configure.in b/configure.in
index 40eb7e558..f8c28ad34 100644
--- a/configure.in
+++ b/configure.in
@@ -584,9 +584,12 @@ outfile_EOF
   fi 
   if test -n "$gint64"; then
     cat >>$outfile <<outfile_EOF
-#define G_HAVE_GINT64 1
-typedef signed $gint64 gint64;
-typedef unsigned $gint64 guint64;
+${glib_warning_guard}#define G_HAVE_GINT64 1
+
+${glib_extension}typedef signed $gint64 gint64;
+${glib_extension}typedef unsigned $gint64 guint64;
+
+#define G_GINT64_CONSTANT(val)	$gint64_constant
 outfile_EOF
   fi 
 
@@ -703,9 +706,31 @@ $ac_cv_sizeof_int)		gint32=int;;
 $ac_cv_sizeof_long)		gint32=long;;
 esac
 case 8 in
-$ac_cv_sizeof_int)		gint64=int;;
-$ac_cv_sizeof_long)		gint64=long;;
-$ac_cv_sizeof_long_long)	gint64='long long';;
+$ac_cv_sizeof_int)
+  gint64=int
+  glib_extension=
+  glib_warning_guard=
+  gint64_constant='(val)'
+  ;;
+$ac_cv_sizeof_long)
+  gint64=long
+  glib_extension=
+  glib_warning_guard=
+  gint64_constant='(val##L)'
+  ;;
+$ac_cv_sizeof_long_long)
+  gint64='long long'
+  glib_extension='GLIB_WARNINGS_MAKE_PEOPLE_CRY '
+  glib_warning_guard="
+#if defined (__GNUC__) && __GNUC__ >= 2 && __GNUC_MINOR__ >= 8
+#  define GLIB_WARNINGS_MAKE_PEOPLE_CRY __extension__
+#else
+#  define GLIB_WARNINGS_MAKE_PEOPLE_CRY
+#endif
+
+"
+  gint64_constant='(GLIB_WARNINGS_MAKE_PEOPLE_CRY (val##LL))'
+  ;;
 esac
 
 gintbits=`expr $ac_cv_sizeof_int \* 8`
diff --git a/glib.h b/glib.h
index 9e9383683..9f6c517a7 100644
--- a/glib.h
+++ b/glib.h
@@ -301,9 +301,9 @@ extern "C" {
 /* Hacker macro to place breakpoints for x86 machines.
  * Actual use is strongly deprecated of course ;)
  */
-#if defined (__i386__) && defined (__GNUC__)
+#if defined (__i386__) && defined (__GNUC__) && __GNUC__ >= 2
 #define	G_BREAKPOINT()		G_STMT_START{ __asm__ __volatile__ ("int $03"); }G_STMT_END
-#elif defined (__alpha__) && defined (__GNUC__)
+#elif defined (__alpha__) && defined (__GNUC__) && __GNUC__ >= 2
 #define	G_BREAKPOINT()		G_STMT_START{ __asm__ __volatile__ ("bpt"); }G_STMT_END
 #else	/* !__i386__ && !__alpha__ */
 #define	G_BREAKPOINT()
@@ -533,37 +533,34 @@ typedef gint32	GTime;
 
 /* Intel specific stuff for speed
  */
-#if defined (__i386__) && (defined __GNUC__)
+#if defined (__i386__) && defined (__GNUC__) && __GNUC__ >= 2
 
 #  define GUINT16_SWAP_LE_BE_X86(val) \
-     (__extension__						\
-      ({ register guint16 __v;					\
-	 if (__builtin_constant_p (val))			\
-	   __v = GUINT16_SWAP_LE_BE_CONSTANT (val);		\
-	 else							\
-	   __asm__ __volatile__ ("rorw $8, %w0"			\
-				 : "=r" (__v)			\
-				 : "0" ((guint16) (val))	\
-				 : "cc");			\
+     (__extension__					\
+      ({ register guint16 __v;				\
+	 if (__builtin_constant_p (val))		\
+	   __v = GUINT16_SWAP_LE_BE_CONSTANT (val);	\
+	 else						\
+	   __asm__ __const__ ("rorw $8, %w0"		\
+			      : "=r" (__v)		\
+			      : "0" ((guint16) (val)));	\
 	__v; }))
 
-#  define GUINT16_SWAP_LE_BE(val) \
-     ((guint16) GUINT16_SWAP_LE_BE_X86 ((guint16) (val)))
+#  define GUINT16_SWAP_LE_BE(val) (GUINT16_SWAP_LE_BE_X86 (val))
 
 #  if !defined(__i486__) && !defined(__i586__) \
-      && !defined(__pentium__) && !defined(__pentiumpro__) && !defined(__i686__)
+      && !defined(__pentium__) && !defined(__i686__) && !defined(__pentiumpro__)
 #     define GUINT32_SWAP_LE_BE_X86(val) \
         (__extension__						\
          ({ register guint32 __v;				\
 	    if (__builtin_constant_p (val))			\
 	      __v = GUINT32_SWAP_LE_BE_CONSTANT (val);		\
 	  else							\
-	    __asm__ __volatile__ ("rorw $8, %w0\n\t"		\
-				  "rorl $16, %0\n\t"		\
-				  "rorw $8, %w0"		\
-				  : "=r" (__v)			\
-				  : "0" ((guint32) (val))	\
-				  : "cc");			\
+	    __asm__ __const__ ("rorw $8, %w0\n\t"		\
+			       "rorl $16, %0\n\t"		\
+			       "rorw $8, %w0"			\
+			       : "=r" (__v)			\
+			       : "0" ((guint32) (val)));	\
 	__v; }))
 
 #  else /* 486 and higher has bswap */
@@ -573,14 +570,13 @@ typedef gint32	GTime;
 	    if (__builtin_constant_p (val))			\
 	      __v = GUINT32_SWAP_LE_BE_CONSTANT (val);		\
 	  else							\
-	    __asm__ __volatile__ ("bswap %0"			\
-				  : "=r" (__v)			\
-				  : "0" ((guint32) (val)));	\
+	    __asm__ __const__ ("bswap %0"			\
+			       : "=r" (__v)			\
+			       : "0" ((guint32) (val)));	\
 	__v; }))
 #  endif /* processor specific 32-bit stuff */
 
-#  define GUINT32_SWAP_LE_BE(val) \
-     ((guint32) GUINT32_SWAP_LE_BE_X86 ((guint32) (val)))
+#  define GUINT32_SWAP_LE_BE(val) (GUINT32_SWAP_LE_BE_X86 (val))
 
 #else /* !__i386__ */
 #  define GUINT16_SWAP_LE_BE(val) (GUINT16_SWAP_LE_BE_CONSTANT (val))
@@ -588,15 +584,46 @@ typedef gint32	GTime;
 #endif /* __i386__ */
 
 #ifdef G_HAVE_GINT64
-#define GUINT64_SWAP_LE_BE(val)         ((guint64) ( \
-    (((guint64) (val) & (guint64) 0x00000000000000ffU) << 56) | \
-    (((guint64) (val) & (guint64) 0x000000000000ff00U) << 40) | \
-    (((guint64) (val) & (guint64) 0x0000000000ff0000U) << 24) | \
-    (((guint64) (val) & (guint64) 0x00000000ff000000U) <<  8) | \
-    (((guint64) (val) & (guint64) 0x000000ff00000000U) >>  8) | \
-    (((guint64) (val) & (guint64) 0x0000ff0000000000U) >> 24) | \
-    (((guint64) (val) & (guint64) 0x00ff000000000000U) >> 40) | \
-    (((guint64) (val) & (guint64) 0xff00000000000000U) >> 56)))
+#  define GUINT64_SWAP_LE_BE_CONSTANT(val)	((guint64) ( \
+      (((guint64) (val) &						\
+	(guint64) G_GINT64_CONSTANT(0x00000000000000ffU)) << 56) |	\
+      (((guint64) (val) &						\
+	(guint64) G_GINT64_CONSTANT(0x000000000000ff00U)) << 40) |	\
+      (((guint64) (val) &						\
+	(guint64) G_GINT64_CONSTANT(0x0000000000ff0000U)) << 24) |	\
+      (((guint64) (val) &						\
+	(guint64) G_GINT64_CONSTANT(0x00000000ff000000U)) <<  8) |	\
+      (((guint64) (val) &						\
+	(guint64) G_GINT64_CONSTANT(0x000000ff00000000U)) >>  8) |	\
+      (((guint64) (val) &						\
+	(guint64) G_GINT64_CONSTANT(0x0000ff0000000000U)) >> 24) |	\
+      (((guint64) (val) &						\
+	(guint64) G_GINT64_CONSTANT(0x00ff000000000000U)) >> 40) |	\
+      (((guint64) (val) &						\
+	(guint64) G_GINT64_CONSTANT(0xff00000000000000U)) >> 56)))
+
+#  if defined (__i386__) && defined (__GNUC__) && __GNUC__ >= 2
+#    define GUINT64_SWAP_LE_BE_X86(val) \
+	(__extension__						\
+	 ({ union { guint64 __ll;				\
+		    guint32 __l[2]; } __r;			\
+	    if (__builtin_constant_p (val))			\
+	      __r.__ll = GUINT64_SWAP_LE_BE_CONSTANT (val);	\
+	    else						\
+	      {							\
+	 	union { guint64 __ll;				\
+			guint32 __l[2]; } __w;			\
+		__w.__ll = ((guint64) val);			\
+		__r.__l[0] = GUINT32_SWAP_LE_BE (__w.__l[1]);	\
+		__r.__l[1] = GUINT32_SWAP_LE_BE (__w.__l[0]);	\
+	      }							\
+	  __r.__ll; }))
+
+#    define GUINT64_SWAP_LE_BE(val) (GUINT64_SWAP_LE_BE_X86 (val))
+
+#  else /* !__i386__ */
+#    define GUINT64_SWAP_LE_BE(val) (GUINT64_SWAP_LE_BE_CONSTANT(val))
+#  endif
 #endif
 
 #define GUINT16_SWAP_LE_PDP(val)	((guint16) (val))
diff --git a/glib/glib.h b/glib/glib.h
index 9e9383683..9f6c517a7 100644
--- a/glib/glib.h
+++ b/glib/glib.h
@@ -301,9 +301,9 @@ extern "C" {
 /* Hacker macro to place breakpoints for x86 machines.
  * Actual use is strongly deprecated of course ;)
  */
-#if defined (__i386__) && defined (__GNUC__)
+#if defined (__i386__) && defined (__GNUC__) && __GNUC__ >= 2
 #define	G_BREAKPOINT()		G_STMT_START{ __asm__ __volatile__ ("int $03"); }G_STMT_END
-#elif defined (__alpha__) && defined (__GNUC__)
+#elif defined (__alpha__) && defined (__GNUC__) && __GNUC__ >= 2
 #define	G_BREAKPOINT()		G_STMT_START{ __asm__ __volatile__ ("bpt"); }G_STMT_END
 #else	/* !__i386__ && !__alpha__ */
 #define	G_BREAKPOINT()
@@ -533,37 +533,34 @@ typedef gint32	GTime;
 
 /* Intel specific stuff for speed
  */
-#if defined (__i386__) && (defined __GNUC__)
+#if defined (__i386__) && defined (__GNUC__) && __GNUC__ >= 2
 
 #  define GUINT16_SWAP_LE_BE_X86(val) \
-     (__extension__						\
-      ({ register guint16 __v;					\
-	 if (__builtin_constant_p (val))			\
-	   __v = GUINT16_SWAP_LE_BE_CONSTANT (val);		\
-	 else							\
-	   __asm__ __volatile__ ("rorw $8, %w0"			\
-				 : "=r" (__v)			\
-				 : "0" ((guint16) (val))	\
-				 : "cc");			\
+     (__extension__					\
+      ({ register guint16 __v;				\
+	 if (__builtin_constant_p (val))		\
+	   __v = GUINT16_SWAP_LE_BE_CONSTANT (val);	\
+	 else						\
+	   __asm__ __const__ ("rorw $8, %w0"		\
+			      : "=r" (__v)		\
+			      : "0" ((guint16) (val)));	\
 	__v; }))
 
-#  define GUINT16_SWAP_LE_BE(val) \
-     ((guint16) GUINT16_SWAP_LE_BE_X86 ((guint16) (val)))
+#  define GUINT16_SWAP_LE_BE(val) (GUINT16_SWAP_LE_BE_X86 (val))
 
 #  if !defined(__i486__) && !defined(__i586__) \
-      && !defined(__pentium__) && !defined(__pentiumpro__) && !defined(__i686__)
+      && !defined(__pentium__) && !defined(__i686__) && !defined(__pentiumpro__)
 #     define GUINT32_SWAP_LE_BE_X86(val) \
         (__extension__						\
          ({ register guint32 __v;				\
 	    if (__builtin_constant_p (val))			\
 	      __v = GUINT32_SWAP_LE_BE_CONSTANT (val);		\
 	  else							\
-	    __asm__ __volatile__ ("rorw $8, %w0\n\t"		\
-				  "rorl $16, %0\n\t"		\
-				  "rorw $8, %w0"		\
-				  : "=r" (__v)			\
-				  : "0" ((guint32) (val))	\
-				  : "cc");			\
+	    __asm__ __const__ ("rorw $8, %w0\n\t"		\
+			       "rorl $16, %0\n\t"		\
+			       "rorw $8, %w0"			\
+			       : "=r" (__v)			\
+			       : "0" ((guint32) (val)));	\
 	__v; }))
 
 #  else /* 486 and higher has bswap */
@@ -573,14 +570,13 @@ typedef gint32	GTime;
 	    if (__builtin_constant_p (val))			\
 	      __v = GUINT32_SWAP_LE_BE_CONSTANT (val);		\
 	  else							\
-	    __asm__ __volatile__ ("bswap %0"			\
-				  : "=r" (__v)			\
-				  : "0" ((guint32) (val)));	\
+	    __asm__ __const__ ("bswap %0"			\
+			       : "=r" (__v)			\
+			       : "0" ((guint32) (val)));	\
 	__v; }))
 #  endif /* processor specific 32-bit stuff */
 
-#  define GUINT32_SWAP_LE_BE(val) \
-     ((guint32) GUINT32_SWAP_LE_BE_X86 ((guint32) (val)))
+#  define GUINT32_SWAP_LE_BE(val) (GUINT32_SWAP_LE_BE_X86 (val))
 
 #else /* !__i386__ */
 #  define GUINT16_SWAP_LE_BE(val) (GUINT16_SWAP_LE_BE_CONSTANT (val))
@@ -588,15 +584,46 @@ typedef gint32	GTime;
 #endif /* __i386__ */
 
 #ifdef G_HAVE_GINT64
-#define GUINT64_SWAP_LE_BE(val)         ((guint64) ( \
-    (((guint64) (val) & (guint64) 0x00000000000000ffU) << 56) | \
-    (((guint64) (val) & (guint64) 0x000000000000ff00U) << 40) | \
-    (((guint64) (val) & (guint64) 0x0000000000ff0000U) << 24) | \
-    (((guint64) (val) & (guint64) 0x00000000ff000000U) <<  8) | \
-    (((guint64) (val) & (guint64) 0x000000ff00000000U) >>  8) | \
-    (((guint64) (val) & (guint64) 0x0000ff0000000000U) >> 24) | \
-    (((guint64) (val) & (guint64) 0x00ff000000000000U) >> 40) | \
-    (((guint64) (val) & (guint64) 0xff00000000000000U) >> 56)))
+#  define GUINT64_SWAP_LE_BE_CONSTANT(val)	((guint64) ( \
+      (((guint64) (val) &						\
+	(guint64) G_GINT64_CONSTANT(0x00000000000000ffU)) << 56) |	\
+      (((guint64) (val) &						\
+	(guint64) G_GINT64_CONSTANT(0x000000000000ff00U)) << 40) |	\
+      (((guint64) (val) &						\
+	(guint64) G_GINT64_CONSTANT(0x0000000000ff0000U)) << 24) |	\
+      (((guint64) (val) &						\
+	(guint64) G_GINT64_CONSTANT(0x00000000ff000000U)) <<  8) |	\
+      (((guint64) (val) &						\
+	(guint64) G_GINT64_CONSTANT(0x000000ff00000000U)) >>  8) |	\
+      (((guint64) (val) &						\
+	(guint64) G_GINT64_CONSTANT(0x0000ff0000000000U)) >> 24) |	\
+      (((guint64) (val) &						\
+	(guint64) G_GINT64_CONSTANT(0x00ff000000000000U)) >> 40) |	\
+      (((guint64) (val) &						\
+	(guint64) G_GINT64_CONSTANT(0xff00000000000000U)) >> 56)))
+
+#  if defined (__i386__) && defined (__GNUC__) && __GNUC__ >= 2
+#    define GUINT64_SWAP_LE_BE_X86(val) \
+	(__extension__						\
+	 ({ union { guint64 __ll;				\
+		    guint32 __l[2]; } __r;			\
+	    if (__builtin_constant_p (val))			\
+	      __r.__ll = GUINT64_SWAP_LE_BE_CONSTANT (val);	\
+	    else						\
+	      {							\
+	 	union { guint64 __ll;				\
+			guint32 __l[2]; } __w;			\
+		__w.__ll = ((guint64) val);			\
+		__r.__l[0] = GUINT32_SWAP_LE_BE (__w.__l[1]);	\
+		__r.__l[1] = GUINT32_SWAP_LE_BE (__w.__l[0]);	\
+	      }							\
+	  __r.__ll; }))
+
+#    define GUINT64_SWAP_LE_BE(val) (GUINT64_SWAP_LE_BE_X86 (val))
+
+#  else /* !__i386__ */
+#    define GUINT64_SWAP_LE_BE(val) (GUINT64_SWAP_LE_BE_CONSTANT(val))
+#  endif
 #endif
 
 #define GUINT16_SWAP_LE_PDP(val)	((guint16) (val))
diff --git a/testglib.c b/testglib.c
index 3a20d62a6..6a763899f 100644
--- a/testglib.c
+++ b/testglib.c
@@ -324,7 +324,8 @@ main (int   argc,
   guint16 gu16t1 = 0x44afU, gu16t2 = 0xaf44U;
   guint32 gu32t1 = 0x02a7f109U, gu32t2 = 0x09f1a702U;
 #ifdef G_HAVE_GINT64
-  guint64 gu64t1 = 0x1d636b02300a7aa7U, gu64t2 = 0xa77a0a30026b631dU;
+  guint64 gu64t1 = G_GINT64_CONSTANT(0x1d636b02300a7aa7U),
+	  gu64t2 = G_GINT64_CONSTANT(0xa77a0a30026b631dU);
 #endif
 
   g_print ("TestGLib v%u.%u.%u (i:%u b:%u)\n",
diff --git a/tests/testglib.c b/tests/testglib.c
index 3a20d62a6..6a763899f 100644
--- a/tests/testglib.c
+++ b/tests/testglib.c
@@ -324,7 +324,8 @@ main (int   argc,
   guint16 gu16t1 = 0x44afU, gu16t2 = 0xaf44U;
   guint32 gu32t1 = 0x02a7f109U, gu32t2 = 0x09f1a702U;
 #ifdef G_HAVE_GINT64
-  guint64 gu64t1 = 0x1d636b02300a7aa7U, gu64t2 = 0xa77a0a30026b631dU;
+  guint64 gu64t1 = G_GINT64_CONSTANT(0x1d636b02300a7aa7U),
+	  gu64t2 = G_GINT64_CONSTANT(0xa77a0a30026b631dU);
 #endif
 
   g_print ("TestGLib v%u.%u.%u (i:%u b:%u)\n",