diff -urN rpm-4.0.3.orig/build/pack.c rpm-4.0.3/build/pack.c
--- rpm-4.0.3.orig/build/pack.c	Tue Apr 17 22:26:32 2001
+++ rpm-4.0.3/build/pack.c	Sun Jun 17 18:14:31 2001
@@ -443,8 +443,20 @@
 
 	if (Fileno(csa->cpioFdIn) < 0) {
 #ifndef	DYING
+	  if (headerIsEntry(h, RPMTAG_ARCH)) {
+	    char *_arch;
+	    headerGetEntry(h, RPMTAG_ARCH, NULL, (void **)&_arch, NULL);
+	    rpmGetArchNum(_arch, &archnum);
+	  } else {
 	    rpmGetArchInfo(NULL, &archnum);
+	  }
+	  if (headerIsEntry(h, RPMTAG_OS)) {
+	    char *_os;
+	    headerGetEntry(h, RPMTAG_OS, NULL, (void **)&_os, NULL);
+	    rpmGetOsNum(_os, &osnum);
+	  } else {
 	    rpmGetOsInfo(NULL, &osnum);
+	  }
 #endif
 	} else if (csa->lead != NULL) {
 	    archnum = csa->lead->archnum;
diff -urN rpm-3.0.4.orig/build/parsePreamble.c rpm-3.0.4/build/parsePreamble.c
--- rpm-3.0.4.orig/build/parsePreamble.c	Tue Aug 24 17:09:22 1999
+++ rpm-3.0.4/build/parsePreamble.c	Thu Sep 30 20:11:20 1999
@@ -140,6 +140,7 @@
 {
     const char *arch = NULL;
     const char *os = NULL;
+    Package pkg;
 
     rpmGetArchInfo(&arch, NULL);
     rpmGetOsInfo(&os, NULL);
@@ -154,6 +155,23 @@
 	rpmError(RPMERR_BADSPEC, _("Architecture is not included: %s"), arch);
 	return RPMERR_BADSPEC;
     }
+    pkg = spec->packages;
+    while (pkg) {
+       if (headerIsEntry(pkg->header, RPMTAG_ARCH)) {
+           headerGetEntry(pkg->header, RPMTAG_ARCH, NULL, (void **)&arch, NULL);
+           if (isMemberInEntry(spec->buildRestrictions,
+                               arch, RPMTAG_EXCLUDEARCH) == 1) {
+               rpmError(RPMERR_BADSPEC, _("Architecture is excluded: %s"), arch);
+               return RPMERR_BADSPEC;
+           }
+           if (isMemberInEntry(spec->buildRestrictions,
+                       arch, RPMTAG_EXCLUSIVEARCH) == 0) {
+               rpmError(RPMERR_BADSPEC, _("Architecture is not included: %s"), arch);
+               return RPMERR_BADSPEC;
+           }
+       }
+       pkg = pkg->next;
+    }
     if (isMemberInEntry(spec->buildRestrictions,
 			os, RPMTAG_EXCLUDEOS) == 1) {
 	rpmError(RPMERR_BADSPEC, _("OS is excluded: %s"), os);
@@ -164,6 +182,23 @@
 	rpmError(RPMERR_BADSPEC, _("OS is not included: %s"), os);
 	return RPMERR_BADSPEC;
     }
+    pkg = spec->packages;
+    while (pkg) {
+       if (headerIsEntry(pkg->header, RPMTAG_OS)) {
+           headerGetEntry(pkg->header, RPMTAG_OS, NULL, (void **)&os, NULL);
+           if (isMemberInEntry(spec->buildRestrictions,
+                               os, RPMTAG_EXCLUDEOS) == 1) {
+               rpmError(RPMERR_BADSPEC, _("OS is excluded: %s"), os);
+               return RPMERR_BADSPEC;
+           }
+           if (isMemberInEntry(spec->buildRestrictions,
+                               os, RPMTAG_EXCLUSIVEOS) == 0) {
+               rpmError(RPMERR_BADSPEC, _("OS is not included: %s"), os);
+               return RPMERR_BADSPEC;
+           }
+       }
+       pkg = pkg->next;
+    }
 
     return 0;
 }
@@ -367,6 +402,8 @@
       case RPMTAG_NAME:
       case RPMTAG_VERSION:
       case RPMTAG_RELEASE:
+      case RPMTAG_ARCH:
+      case RPMTAG_OS:
       case RPMTAG_URL:
 	SINGLE_TOKEN_ONLY;
 	/* These macros are for backward compatibility */
@@ -611,7 +648,9 @@
     {RPMTAG_AUTOREQPROV,	0, 0, "autoreqprov"},
     {RPMTAG_AUTOREQ,		0, 0, "autoreq"},
     {RPMTAG_AUTOPROV,		0, 0, "autoprov"},
-    {RPMTAG_DOCDIR,		0, 0, "docdir"},
+    {RPMTAG_DOCDIR,		0, 0, "docdir"},
+    {RPMTAG_ARCH,		0, 0, "targetarch"},
+    {RPMTAG_OS,			0, 0, "targetos"},
     {0, 0, 0, 0}
 };
 
diff -urN rpm-3.0.3.orig/build/parseSpec.c rpm-3.0.3/build/parseSpec.c
--- rpm-3.0.3.orig/build/parseSpec.c	Mon Sep  6 23:51:54 1999
+++ rpm-3.0.3/build/parseSpec.c	Thu Sep 30 20:11:20 1999
@@ -496,8 +496,10 @@
 	    return RPMERR_BADSPEC;
 	}
 
-	headerAddEntry(pkg->header, RPMTAG_OS, RPM_STRING_TYPE, os, 1);
-	headerAddEntry(pkg->header, RPMTAG_ARCH, RPM_STRING_TYPE, arch, 1);
+       if (!headerIsEntry(pkg->header, RPMTAG_OS))
+           headerAddEntry(pkg->header, RPMTAG_OS, RPM_STRING_TYPE, os, 1);
+       if (!headerIsEntry(pkg->header, RPMTAG_ARCH))
+           headerAddEntry(pkg->header, RPMTAG_ARCH, RPM_STRING_TYPE, arch, 1);
       }
       FREE(myos);
     }
diff -urN rpm-4.0.3.orig/lib/rpmlib.h rpm-4.0.3/lib/rpmlib.h
--- rpm-4.0.3.orig/lib/rpmlib.h	Thu Apr 19 18:11:00 2001
+++ rpm-4.0.3/lib/rpmlib.h	Sun Jun 17 18:08:16 2001
@@ -475,6 +475,7 @@
  * @retval num		address of arch number (or NULL)
  */
 void rpmGetArchInfo( /*@out@*/ const char ** name, /*@out@*/ int * num);
+void rpmGetArchNum(char * name, int * num);
 
 /** \ingroup rpmrc
  * Return current os name and/or number.
@@ -483,6 +484,7 @@
  * @retval num		address of os number (or NULL)
  */
 void rpmGetOsInfo( /*@out@*/ const char ** name, /*@out@*/ int * num);
+void rpmGetOsNum(char * name, int * num);
 
 /** \ingroup rpmrc
  * Return arch/os score of a name.
diff -urN rpm-3.0.3.orig/lib/rpmrc.c rpm-3.0.3/lib/rpmrc.c
--- rpm-3.0.3.orig/lib/rpmrc.c	Mon Aug 16 19:05:03 1999
+++ rpm-3.0.3/lib/rpmrc.c	Thu Sep 30 20:11:20 1999
@@ -1136,6 +1136,38 @@
     getMachineInfo(OS, name, num);
 }
 
+static void getNum(int type, char * name, int * num) {
+    struct canonEntry * canon;
+    int which = currTables[type];
+
+    /* use the normal canon tables, even if we're looking up build stuff */
+    if (which >= 2) which -= 2;
+
+    canon = lookupInCanonTable(name, 
+			       tables[which].canons,
+			       tables[which].canonsLength);
+
+    if (canon) {
+	if (num) *num = canon->num;
+    } else {
+	if (num) *num = 255;
+
+	if (tables[currTables[type]].hasCanon) {
+	    rpmMessage(RPMMESS_WARNING, _("Unknown system: %s\n"), name);
+/*	    rpmMessage(RPMMESS_WARNING, _("Please contact rpm-list@redhat.com\n"));*/
+	}
+    }
+}
+
+void rpmGetArchNum(char * name, int * num) {
+    getNum(ARCH, name, num);
+}
+
+void rpmGetOsNum(char * name, int * num) {
+    getNum(OS, name, num);
+}
+
+
 void rpmRebuildTargetVars(const char **buildtarget, const char ** canontarget)
 {