Pacify gcc in xpm_scan

* src/image.c (xpm_scan): Redo a loop for clarity.
This also pacifies --enable-gcc-warnings (GCC 9.3.1 x86-64 with -Og).

1 files changed, 3 insertions, 2 deletions

diff --git a/src/image.c b/src/image.c
index 65d59254f02..c98ca291ca5 100644
--- a/src/image.c
+++ b/src/image.c
@@ -4572,8 +4572,9 @@ xpm_scan (const char **s, const char *end, const char **beg, ptrdiff_t *len)
   while (*s < end)
     {
       /* Skip white-space.  */
-      while (*s < end && (c = *(*s)++, c_isspace (c)))
-        ;
+      do
+        c = *(*s)++;
+      while (c_isspace (c) && *s < end);
 
       /* gnus-pointer.xpm uses '-' in its identifier.
          sb-dir-plus.xpm uses '+' in its identifier.  */