--- qmake/generators/unix/unixmake.cpp.framework
+++ qmake/generators/unix/unixmake.cpp
@@ -589,9 +589,11 @@
     libdirs.append(QMakeLocalFileName("@PREFIX@/lib"));
     const QString lflags[] = { "QMAKE_LIBDIR_FLAGS", "QMAKE_FRAMEWORKPATH_FLAGS", "QMAKE_LFLAGS", "QMAKE_LIBS", QString() };
     for(int i = 0; !lflags[i].isNull(); i++) {
+      // warn_msg(WarnLogic, "processPrlFiles: 0: lflags[%d] is '%s'", i, lflags[i].toLatin1().constData());
         QStringList &l = project->values(lflags[i]);
         for(int lit = 0; lit < l.size(); ++lit) {
             QString opt = l.at(lit).trimmed();
+            // warn_msg(WarnLogic, "processPrlFiles: 1: opt[%d] is '%s'", lit, opt.toLatin1().constData());
             if(opt.startsWith("-")) {
                 if(opt.startsWith("-L")) {
                     QMakeLocalFileName l(opt.right(opt.length()-2));
@@ -727,6 +729,7 @@
             for(int lit = 0; lit < l.size(); ++lit) {
                 QString arch("default");
                 QString opt = l.at(lit).trimmed();
+                // warn_msg(WarnLogic, "processPrlFiles: 2: opt[%d] is '%s'", lit, opt.toLatin1().constData());
                 if(opt.startsWith("-")) {
                     if (Option::target_mode == Option::TARG_MACX_MODE && opt.startsWith("-Xarch")) {
                         if (opt.length() > 7) {
@@ -734,7 +737,7 @@
                             opt = l.at(++lit);
                         }
                     }
-
+                    // warn_msg(WarnLogic, "processPrlFiles: 2: arch is '%s'", arch.toLatin1().constData());
                     if(opt.startsWith("-L") ||
                        (Option::target_mode == Option::TARG_MACX_MODE && opt.startsWith("-F"))) {
                         if(!lflags[arch].contains(opt))
@@ -771,6 +774,55 @@
                             lflags[arch].append("-framework");
                             lflags[arch].append(opt);
                         }
+                    } else if (Option::target_mode == Option::TARG_MACX_MODE && opt.startsWith("-arch")) {
+                      // warn_msg(WarnLogic, "%d / %d: %s, %s", lit, l.size (), opt.toLatin1().constData(), l.at(lit).toLatin1().constData(), l.at(1+lit).toLatin1().constData());
+                      // make sure "-arch" is exact
+                      if (opt.toLower() != "-arch") {
+                        warn_msg(WarnLogic, "Expect '-arch' flag to be standalone; got '%s'; ignoring extra.", opt.toLatin1().constData());
+                      }
+                      // retrieve the next argument, if it exists
+                      if (++lit >= l.size ()) {
+                        warn_msg(WarnLogic, "Lone '-arch' flag; ignoring.");
+                        continue;
+                      }
+                      QString t_arch = l.at(lit).trimmed().toLower();
+                      // make sure next option is valid
+                      const QString archs[] = { "i386", "x86_64", "ppc64", "ppc", QString() };
+                      int i = 0;
+                      for(; !archs[i].isNull(); ++i) {
+                        if (t_arch.startsWith(archs[i])) {
+                          break;
+                        }
+                      }
+                      if (archs[i].isNull()) {
+                        warn_msg(WarnLogic, "Lone '-arch' flag; ignoring.");
+                        --lit;
+                        continue;
+                      }
+                      // make sure the option is exact
+                      if (archs[i] != t_arch) {
+                        warn_msg(WarnLogic, "Expect ARCH of '-arch ARCH' flag to be exact; got '%s'; ignoring extra.", t_arch.toLatin1().constData());
+                        t_arch = archs[i];
+                      }
+                      // see if this flag is alread in place in the ldflags
+                      // for "default" and the selected arch.
+                      // is "-arch ARCH" already in any set of flags?
+                      bool found = false;
+                      for(int j = 0; j < lflags["default"].size(); ++j) {
+                        if ((lflags[arch].at(j) == "-arch") &&
+                            (lflags[arch].at(j+1) == t_arch)) {
+                          // yes: flag already exists; ignore it
+                          found = true;
+                          break;
+                        }
+                      }
+                      if (!found) {
+                        // no: add it
+                        lflags[arch].append("-arch");
+                        lflags[arch].append(t_arch);
+                      } else {
+                        warn_msg(WarnLogic, "Found duplicate '-arch %s' flag; ignoring.", t_arch.toLatin1().constData());
+                      }
                     } else {
                         lflags[arch].append(opt);
                     }
