Revert commit that breaks sis installation

source-builder/config/sis-2-1.cfg

@@ -31,19 +31,26 @@ Release:   %{release}
 
   cd sis-%{sis_version}
 
+  ac_prefix=%{_prefix}
+
+  if test "%{_build}" != "%{_host}" ; then
+    CFLAGS_FOR_BUILD="-g -O2 -Wall"
+  fi
+  export CFLAGS CFLAGS_FOR_BUILD CC
+
   if test "%{_target}" != "" ; then
     SIS_PREFIX="%{_target}-"
   fi
-
-  %{host_build_flags}
-
+  CFLAGS="$SB_CFLAGS" \
   ./configure \
-    --build=%{_build} --host=%{_host} --target=%{_target} \
+    --build=%{_build} --host=%{_host} \
     --program-prefix="$SIS_PREFIX" \
-    --prefix=${_prefix}
+    --prefix=${ac_prefix}
 
   %{__make} %{?_smp_mflags} all
 
+  unset CFLAGS_FOR_BUILD
+
   cd ${build_top}
 
 %install