diff --git a/filter/pdftopdf/P2POutputStream.h b/filter/pdftopdf/P2POutputStream.h
index 3de6a6b..f4b0e37 100644
--- a/filter/pdftopdf/P2POutputStream.h
+++ b/filter/pdftopdf/P2POutputStream.h
@@ -36,6 +36,7 @@ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #undef HAVE_LIBZ
 #endif
 #include <stdio.h>
+#undef putchar
 #ifdef HAVE_LIBZ
 #include <zlib.h>
 #endif