diff -urN rpm.org/build/parseSpec.c rpm/build/parseSpec.c
--- rpm.org/build/parseSpec.c	2004-06-14 14:52:54.433793272 +0200
+++ rpm/build/parseSpec.c	2004-06-14 14:55:21.399451096 +0200
@@ -227,6 +227,15 @@
     return 0;
 }
 /*@=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)
@@ -319,13 +328,15 @@
 	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.org/lib/rpmrc.c rpm/lib/rpmrc.c
--- rpm.org/lib/rpmrc.c	2004-06-14 14:53:19.117040848 +0200
+++ rpm/lib/rpmrc.c	2004-06-14 14:55:21.421447752 +0200
@@ -1319,6 +1319,13 @@
 	}
 #	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.org/rpmrc.in rpm/rpmrc.in
--- rpm.org/rpmrc.in	2004-06-14 14:53:29.723428432 +0200
+++ rpm/rpmrc.in	2004-06-14 14:58:38.156539472 +0200
@@ -272,9 +272,9 @@
 
 buildarchtranslate: ia64: ia64
 
-buildarchtranslate: x86_64: x86_64
-buildarchtranslate: amd64: x86_64
-buildarchtranslate: ia32e: x86_64
+buildarchtranslate: x86_64: amd64
+buildarchtranslate: amd64: amd64
+buildarchtranslate: ia32e: amd64
 
 #############################################################
 # Architecture compatibility
diff -urN rpm.org/configure.ac rpm/configure.ac
--- rpm.org/configure.ac	2004-07-02 23:11:17.214544320 +0200
+++ rpm/configure.ac	2004-07-02 23:11:43.369568152 +0200
@@ -1110,7 +1110,7 @@
 *86)		RPMCANONCOLOR=0; RPMCANONARCH=i386 ;;
 ia32e*)		RPMCANONCOLOR=3; RPMCANONARCH=ia32e ;;
 amd64*)		RPMCANONCOLOR=3; RPMCANONARCH=amd64 ;;
-x86_64*)	RPMCANONCOLOR=3; RPMCANONARCH=x86_64 ;;
+x86_64*)	RPMCANONCOLOR=3; RPMCANONARCH=amd64 ;;
 alpha*)		RPMCANONCOLOR=0; RPMCANONARCH=alpha ;;
 sparc64*)	RPMCANONCOLOR=3; RPMCANONARCH=sparc64 ;;
 sparc*)		RPMCANONCOLOR=3; RPMCANONARCH=sparc ;;