- silence warning about possibly undefined preprocessor token

diff --git a/libc/string/generic/pagecopy.h b/libc/string/generic/pagecopy.h
index 5a0ada1..b00db49 100644 (file)
--- a/libc/string/generic/pagecopy.h
+++ b/libc/string/generic/pagecopy.h
@@ -40,7 +40,7 @@
 */
 
 
-#if PAGE_COPY_THRESHOLD
+#if defined PAGE_COPY_THRESHOLD && PAGE_COPY_THRESHOLD
 
 #include <assert.h>
 
@@ -48,7 +48,7 @@
   do                                                                         \
     {                                                                        \
       if ((nbytes) >= PAGE_COPY_THRESHOLD &&                                 \
-         PAGE_OFFSET ((dstp) - (srcp)) == 0)                                 \
+         PAGE_OFFSET ((dstp) - (srcp)) == 0)                                 \
        {                                                                     \
          /* The amount to copy is past the threshold for copying             \
             pages virtually with kernel VM operations, and the               \