more macOS whitelisting

X11, Qt, and util

also ensure the functional warnings.h macro definitions are used
with c++ clang compiler

util/panic.c

@@ -22,6 +22,8 @@ extern void vms_abort(void);
 boolean panicking;
 void panic(const char *, ...);
 
+DISABLE_WARNING_FORMAT_NONLITERAL
+
 void panic
 VA_DECL(const char *, str)
 {
@@ -46,6 +48,8 @@ VA_DECL(const char *, str)
     exit(EXIT_FAILURE); /* redundant */
 }
 
+RESTORE_WARNING_FORMAT_NONLITERAL
+
 #ifdef ALLOCA_HACK
 /*
  * In case bison-generated foo_yacc.c tries to use alloca(); if we don't