Port to clang 3.7.0 on x86-64

* configure.ac: Use AS_IF so that gl_WARN_ADD’s prerequisites are
not done conditionally.  This helps clang, which needs
-Wunknown-warning-option later when configured with warnings.
* src/editfns.c (invalid_time): Now _Noreturn, since clang isn’t
smart enough to figure this out on its own if warnings are enabled.
(lisp_time_struct): Redo for clarity, and to pacify clang.
* src/xfns.c (x_real_pos_and_offsets) [USE_XCB]: Don’t use
uninitialized locals.  This avoids undefined behavior and pacifies
clang.

2 files changed, 5 insertions, 3 deletions

diff --git a/src/editfns.c b/src/editfns.c
index df982234977..2ac0537eddb 100644
--- a/src/editfns.c
+++ b/src/editfns.c
@@ -1456,7 +1456,7 @@ time_overflow (void)
   error ("Specified time is not representable");
 }
 
-static void
+static _Noreturn void
 invalid_time (void)
 {
   error ("Invalid time specification");
@@ -1848,7 +1848,9 @@ lisp_time_struct (Lisp_Object specified_time, int *plen)
   Lisp_Object high, low, usec, psec;
   struct lisp_time t;
   int len = disassemble_lisp_time (specified_time, &high, &low, &usec, &psec);
-  int val = len ? decode_time_components (high, low, usec, psec, &t, 0) : 0;
+  if (!len)
+    invalid_time ();
+  int val = decode_time_components (high, low, usec, psec, &t, 0);
   check_time_validity (val);
   *plen = len;
   return t;
diff --git a/src/xfns.c b/src/xfns.c
index 0a4a09ef285..b22af5c830d 100644
--- a/src/xfns.c
+++ b/src/xfns.c
@@ -273,7 +273,7 @@ x_real_pos_and_offsets (struct frame *f,
       XFree (tmp_children);
 #endif
 
-      if (wm_window == rootw || had_errors)
+      if (had_errors || wm_window == rootw)
         break;
 
       win = wm_window;