ast fmtbuf: squash -Wsign-compare warning

This is computing the number of bytes remaining in `buf`; the number of bytes
between a pointer to the current offset and the end of `buf`. Thus it is always
non-negative.

diff --git a/lib/ast/fmtbuf.c b/lib/ast/fmtbuf.c
index 09a58cfe5bc606b45254e4a00ed76b7506abc3b4..ffe99d0b72082916dd2faad4167a925781018d25 100644 (file)
--- a/lib/ast/fmtbuf.c
+++ b/lib/ast/fmtbuf.c
@@ -10,6 +10,7 @@
 
 
 #include <ast/ast.h>
+#include <stddef.h>
 
 /*
  * return small format buffer chunk of size n
@@ -23,7 +24,7 @@ char *fmtbuf(size_t n)
 {
     char *cur;
 
-    if (n > (&buf[elementsof(buf)] - nxt))
+    if (n > (size_t)(&buf[elementsof(buf)] - nxt))
        nxt = buf;
     cur = nxt;
     nxt += n;