gd_xbm: fix fortify warning

When glibc fortify is enabled, we get this warning:

gd_xbm.c: In function 'gdCtxPrintf':
gd_xbm.c:150:2: warning: passing argument 1 of 'vsnprintf' from incompatible pointer type [enabled by default]
  len = vsnprintf(&buf, sizeof(buf)-1, format, args);
                  ^
In file included from /usr/include/stdio.h:937:0,
                 from gd_xbm.c:5:
/usr/include/bits/stdio2.h:74:42: note: expected 'char * __restrict__' but argument is of type 'char (*)[4096]'
 __NTH (vsnprintf (char *__restrict __s, size_t __n,
                                      ^

Since &buf and buf are in practice the same pointer with arrays like
this, drop the & to fix the warning.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/gd_xbm.c b/src/gd_xbm.c
index c6dfae1..a314c99 100644
--- a/src/gd_xbm.c
+++ b/src/gd_xbm.c
@@ -147,7 +147,7 @@ static void gdCtxPrintf(gdIOCtx * out, const char *format, ...)
 	va_list args;
 
 	va_start(args, format);
-	len = vsnprintf(&buf, sizeof(buf)-1, format, args);
+	len = vsnprintf(buf, sizeof(buf)-1, format, args);
 	va_end(args);
 	out->putBuf(out, buf, len);
 }