build: only use DESTDIR instead of PREFIX for pkg

Preserve default install prefix seen in process.config, but use DESTDIR
for installing to deliniate 32/64 versions, avoid conflicts with PREFIX
settings in config.mk

Makefile

@@ -266,11 +266,11 @@ pkg: $(PKG)
 $(PKG): release-only
 	rm -rf $(PKGDIR)
 	rm -rf out/deps out/Release
-	$(PYTHON) ./configure --prefix=$(PKGDIR)/32/usr/local --without-snapshot --dest-cpu=ia32 --tag=$(TAG)
-	$(MAKE) install V=$(V)
+	$(PYTHON) ./configure --without-snapshot --dest-cpu=ia32 --tag=$(TAG)
+	$(MAKE) install V=$(V) DESTDIR=$(PKGDIR)/32
 	rm -rf out/deps out/Release
-	$(PYTHON) ./configure --prefix=$(PKGDIR)/usr/local --without-snapshot --dest-cpu=x64 --tag=$(TAG)
-	$(MAKE) install V=$(V)
+	$(PYTHON) ./configure --without-snapshot --dest-cpu=x64 --tag=$(TAG)
+	$(MAKE) install V=$(V) DESTDIR=$(PKGDIR)
 	SIGN="$(SIGN)" PKGDIR="$(PKGDIR)" bash tools/osx-codesign.sh
 	lipo $(PKGDIR)/32/usr/local/bin/node \
 		$(PKGDIR)/usr/local/bin/node \