Correct typo in blast.c.
diff --git a/contrib/blast/blast.h b/contrib/blast/blast.h
index 6cf65ed..ef8544c 100644
--- a/contrib/blast/blast.h
+++ b/contrib/blast/blast.h
@@ -57,7 +57,7 @@
* use by the application to pass an input descriptor to infun(), if desired.
*
* If left and in are not NULL and *left is not zero when blast() is called,
- * then the *left bytes are *in are consumed for input before infun() is used.
+ * then the *left bytes at *in are consumed for input before infun() is used.
*
* The output function is invoked: err = outfun(how, buf, len), where the bytes
* to be written are buf[0..len-1]. If err is not zero, then blast() returns
