array.c (rb_mem_clear): remove "register" from arguments

to suppress the following warning:

```
compiling cxxanyargs.cpp
In file included from cxxanyargs.cpp:1:
In file included from ../../.././include/ruby/ruby.h:2150:
../../.././include/ruby/intern.h:56:19: warning: 'register' storage class specifier is deprecated and incompatible with C++17 [-Wdeprecated-register]
void rb_mem_clear(register VALUE*, register long);
                  ^~~~~~~~~
../../.././include/ruby/intern.h:56:36: warning: 'register' storage class specifier is deprecated and incompatible with C++17 [-Wdeprecated-register]
void rb_mem_clear(register VALUE*, register long);
                                   ^~~~~~~~~
```

1 files changed, 1 insertions, 1 deletions

diff --git a/array.c b/array.c
index c63bfb3b93..9235bf22e8 100644
--- a/array.c
+++ b/array.c
@@ -240,7 +240,7 @@ rb_ary_ptr_use_end(VALUE ary)
 }
 
 void
-rb_mem_clear(register VALUE *mem, register long size)
+rb_mem_clear(VALUE *mem, long size)
 {
     while (size--) {
 	*mem++ = Qnil;