User Story 1105662: Fix pch.h clang 16 compilation bug

llvm/llvm-project#61931

imgui.h

@@ -54,6 +54,7 @@ Index of this file:
 
 // Includes
 #include <float.h>                  // FLT_MIN, FLT_MAX
+#include <stdio.h>
 #include <stdarg.h>                 // va_list, va_start, va_end
 #include <stddef.h>                 // ptrdiff_t, NULL
 #include <string.h>                 // memset, memmove, memcpy, strlen, strchr, strcpy, strcmp