diff --git a/configure b/configure
index b64e834..a9e7707 100755
--- a/configure
+++ b/configure
@@ -21170,6 +21170,7 @@
 main ()
 {
   char *data, *data2, *data3;
+  const char *cdata2;
   int i, pagesize;
   int fd, fd2;
 
@@ -21194,10 +21195,10 @@
   fd2 = open ("conftest.txt", O_RDWR | O_CREAT | O_TRUNC, 0600);
   if (fd2 < 0)
     return 4;
-  data2 = "";
-  if (write (fd2, data2, 1) != 1)
+  cdata2 = "";
+  if (write (fd2, cdata2, 1) != 1)
     return 5;
-  data2 = mmap (0, pagesize, PROT_READ | PROT_WRITE, MAP_SHARED, fd2, 0L);
+  data2 = (char *) mmap (0, pagesize, PROT_READ | PROT_WRITE, MAP_SHARED, fd2, 0L);
   if (data2 == MAP_FAILED)
     return 6;
   for (i = 0; i < pagesize; ++i)