diff -urN rpm-4.3.org/build/parseSpec.c rpm-4.3/build/parseSpec.c
--- rpm-4.3.org/build/parseSpec.c	2003-11-16 11:30:21.000000000 +0100
+++ rpm-4.3/build/parseSpec.c	2003-11-16 13:53:07.000000000 +0100
@@ -194,6 +194,16 @@
 }
 /*@=boundswrite@*/
 
+static const char *getAlternateArch(const char *arch)
+{
+    const char *alternate_arch = NULL;
+    if (! strncmp("x86_64", arch, sizeof("x86_64")-1))
+      alternate_arch = "amd64";
+    else if (! strncmp("amd64", arch, sizeof("amd64")-1))
+      alternate_arch = "x86_64";
+    return alternate_arch;
+}
+
 /*@-boundswrite@*/
 int readLine(Spec spec, int strip)
 {
@@ -282,13 +292,15 @@
 	match = 0;
     } else if (! strncmp("%ifarch", s, sizeof("%ifarch")-1)) {
 	const char *arch = rpmExpand("%{_target_cpu}", NULL);
+	const char *alternate_arch = getAlternateArch(arch);
 	s += 7;
-	match = matchTok(arch, s);
+	match = matchTok(arch, s) || (alternate_arch && matchTok(alternate_arch, s));
 	arch = _free(arch);
     } else if (! strncmp("%ifnarch", s, sizeof("%ifnarch")-1)) {
 	const char *arch = rpmExpand("%{_target_cpu}", NULL);
+	const char *alternate_arch = getAlternateArch(arch);
 	s += 8;
-	match = !matchTok(arch, s);
+	match = !matchTok(arch, s) && (!alternate_arch || !matchTok(alternate_arch, s));
 	arch = _free(arch);
     } else if (! strncmp("%ifos", s, sizeof("%ifos")-1)) {
 	const char *os = rpmExpand("%{_target_os}", NULL);
diff -urN rpm-4.3.org/installplatform rpm-4.3/installplatform
--- rpm-4.3.org/installplatform	2003-01-10 17:18:55.000000000 +0100
+++ rpm-4.3/installplatform	2003-11-16 13:59:30.000000000 +0100
@@ -34,6 +34,7 @@
   alpha*) SUBSTS='s_alpha_alpha_ s_alpha_alphaev5_ s_alpha_alphaev56_ s_alpha_alphapca56_ s_alpha_alphaev6_ s_alpha_alphaev67_' ;;
   sparc*) SUBSTS='s_sparc\(64\|v9\)_sparc_ s_sparc64_sparcv9_;s_sparc\([^v]\|$\)_sparcv9\1_ s_sparcv9_sparc64_;s_sparc\([^6]\|$\)_sparc64\1_' ;;
   powerpc*|ppc*) SUBSTS='s_ppc64_ppc_ s_ppc\([^6]\|$\)_ppc64\1_' ;;
+  x86_64*|amd64*) SUBSTS="s/${arch}/x86_64/ s/${arch}/amd64/" ;;
   s390*) SUBSTS='s_s390x_s390_ s_s390\([^x]\|$\)_s390x\1_' ;;
   *) SUBSTS=y___ ;;
 esac
@@ -66,7 +67,7 @@
     ppc-linux) MULTILIBNO=1 ;;
     ppc64-linux) LIB=lib64; MULTILIBNO=2 ;;
     i?86-linux|athlon-linux) MULTILIBNO=1 ;;
-    x86_64-linux) LIB=lib64; MULTILIBNO=2 ;;
+    x86_64-linux|amd64-linux) LIB=lib64; MULTILIBNO=2 ;;
   esac
 
   if [ -n "$MULTILIBNO" ]; then
diff -urN rpm-4.3.org/lib/rpmrc.c rpm-4.3/lib/rpmrc.c
--- rpm-4.3.org/lib/rpmrc.c	2003-11-16 11:30:21.000000000 +0100
+++ rpm-4.3/lib/rpmrc.c	2003-11-16 13:50:56.000000000 +0100
@@ -1278,6 +1278,13 @@
 	}
 #	endif
 
+#	if defined(__linux__) && defined(__amd64__)
+	{
+	    /* Defaults to amd64 if compiler supports __amd64__ */
+	    strcpy(un.machine, "amd64");
+	}
+#	endif
+	
 #	if defined(__linux__) && defined(__powerpc__)
 	{
 	    unsigned pvr = 0;
diff -urN rpm-4.3.org/rpmrc.in rpm-4.3/rpmrc.in
--- rpm-4.3.org/rpmrc.in	2003-11-16 11:30:21.000000000 +0100
+++ rpm-4.3/rpmrc.in	2003-11-16 13:56:25.000000000 +0100
@@ -18,7 +18,8 @@
 optflags: i686 -O2 -march=i686%{!?nospecflags:%{?specflags: %{specflags}}%{?specflags_ia32: %{specflags_ia32}}%{?specflags_i686: %{specflags_i686}}}
 optflags: athlon -O2 -march=athlon%{!?nospecflags:%{?specflags: %{specflags}}%{?specflags_ia32: %{specflags_ia32}}%{?specflags_athlon: %{specflags_athlon}}}
 optflags: ia64 -O2%{!?nospecflags:%{?specflags: %{specflags}}%{?specflags_ia64: %{specflags_ia64}}}
-optflags: x86_64 -O2%{!?nospecflags:%{?specflags: %{specflags}}%{?specflags_x86_64: %{specflags_x86_64}}}
+optflags: x86_64 -O2%{!?nospecflags:%{?specflags: %{specflags}}%{?specflags_amd64: %{specflags_amd64}}}
+optflags: amd64 -O2%{!?nospecflags:%{?specflags: %{specflags}}%{?specflags_amd64: %{specflags_amd64}}}
 
 optflags: alpha -O2 -mieee%{!?nospecflags:%{?specflags: %{specflags}}%{?specflags_alpha: %{specflags_alpha}}}
 optflags: alphaev5 -O2 -mieee -mcpu=ev5%{!?nospecflags:%{?specflags: %{specflags}}%{?specflags_alpha: %{specflags_alpha}}%{?specflags_alphaev5: %{specflags_alphaev5}}}
@@ -71,6 +72,7 @@
 arch_canon:	i486:	i486	1
 arch_canon:	i386:	i386	1
 arch_canon:	x86_64:	x86_64	1
+arch_canon:	amd64:	amd64	1
 
 arch_canon:	alpha:	alpha	2
 arch_canon:	alphaev5: alphaev5	2
@@ -201,7 +203,8 @@
 
 buildarchtranslate: ia64: ia64
 
-buildarchtranslate: x86_64: x86_64
+buildarchtranslate: amd64: amd64
+buildarchtranslate: x86_64: amd64
 
 #############################################################
 # Architecture compatibility
@@ -270,6 +273,7 @@
 
 arch_compat: ia64: i686 noarch
 
+arch_compat: amd64: x86_64
 arch_compat: x86_64: athlon noarch
 
 os_compat:   IRIX64: IRIX
@@ -299,6 +303,7 @@
 os_compat: BSD_OS: bsdi
 os_compat: bsdi4.0: bsdi
 
+buildarch_compat: amd64: noarch
 buildarch_compat: ia64: noarch
 
 buildarch_compat: athlon: i686