avoid build problems caused by parallel building

png/png.spec

@@ -33,7 +33,7 @@ Class:        BASE
 Group:        Graphics
 License:      BSD
 Version:      1.2.20
-Release:      20070908
+Release:      20070921
 
 #   list of sources
 Source0:      http://switch.dl.sourceforge.net/sourceforge/libpng/libpng-%{version}.tar.gz
@@ -80,7 +80,7 @@ AutoReqProv:  no
         --mandir=%{l_prefix}/man \
         --with-libpng-compat \
         --disable-shared
-    %{l_make} %{l_mflags -O}
+    %{l_make} %{l_mflags}
 
 %install
     rm -rf $RPM_BUILD_ROOT