Use #ifdef consistently for HAVE_RB_EXT_RACTOR_SAFE

We previously used a mix of both `#if` and `#ifdef`, but the latter is
more reliable because it will still work if the macro is undefined.

Author: tomstuart

ext/openssl/ossl.c

@@ -1129,7 +1129,7 @@ ossl_crypto_fixed_length_secure_compare(VALUE dummy, VALUE str1, VALUE str2)
 void
 Init_openssl(void)
 {
-#if HAVE_RB_EXT_RACTOR_SAFE
+#ifdef HAVE_RB_EXT_RACTOR_SAFE
     rb_ext_ractor_safe(true);
 #endif
 

ext/openssl/ossl_bn.c

@@ -10,7 +10,7 @@
 /* modified by Michal Rokos <m.rokos@sh.cvut.cz> */
 #include "ossl.h"
 
-#if HAVE_RB_EXT_RACTOR_SAFE
+#ifdef HAVE_RB_EXT_RACTOR_SAFE
 #include <ruby/ractor.h>
 #endif
 
@@ -155,7 +155,7 @@ ossl_bn_value_ptr(volatile VALUE *ptr)
  * Private
  */
 
-#if HAVE_RB_EXT_RACTOR_SAFE
+#ifdef HAVE_RB_EXT_RACTOR_SAFE
 void
 ossl_bn_ctx_free(void *ptr)
 {