Pacify clang 15.0.6 on Fedora 37

* configure.ac: Suppress clang -Wbitwise-instead-of-logical,
as there’s nothing wrong with using & and | on bool.
* src/coding.c: Suppress -Wunused-but-set-variable in this file,
as it’s too much trouble to recode to pacify clang.

configure.ac

@@ -1139,6 +1139,7 @@ AS_IF([test $gl_gcc_warnings = no],
 
   # clang is unduly picky about some things.
   if test "$emacs_cv_clang" = yes; then
+    gl_WARN_ADD([-Wno-bitwise-instead-of-logical])
     gl_WARN_ADD([-Wno-missing-braces])
     gl_WARN_ADD([-Wno-null-pointer-arithmetic])
     gl_WARN_ADD([-Wno-implicit-const-int-float-conversion])

src/coding.c

@@ -651,6 +651,12 @@ growable_destination (struct coding_system *coding)
     consumed_chars++;					\
   } while (0)
 
+/* Suppress clang warnings about consumed_chars never being used.
+   Although correct, the warnings are too much trouble to code around.  */
+#if 13 <= __clang_major__
+# pragma clang diagnostic ignored "-Wunused-but-set-variable"
+#endif
+
 /* Safely get two bytes from the source text pointed by SRC which ends
    at SRC_END, and set C1 and C2 to those bytes while skipping the
    heading multibyte characters.  If there are not enough bytes in the