crypto: remove root_cert_store from node_crypto.h

root_cert_store is defined as extern in node_crypto.h but only used in
node_crypto.cc. It is then set using SSL_CTX_set_cert_store. The only
usages of SSL_CTX_get_cert_store are in node_crypto.cc which would all
be accessing the same X509_STORE through the root_cert_store pointer as
far as I can tell. Am I missing something here?

This commit suggests removing it from the header and making it static
in node_crypto.cc.

PR-URL: #13194
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Sam Roberts <vieuxtech@gmail.com>

src/node_crypto.cc

@@ -120,13 +120,13 @@ static X509_NAME *cnnic_ev_name =
 
 static Mutex* mutexes;
 
-const char* const root_certs[] = {
+static const char* const root_certs[] = {
 #include "node_root_certs.h"  // NOLINT(build/include_order)
 };
 
-std::string extra_root_certs_file;  // NOLINT(runtime/string)
+static std::string extra_root_certs_file;  // NOLINT(runtime/string)
 
-X509_STORE* root_cert_store;
+static X509_STORE* root_cert_store;
 
 // Just to generate static methods
 template class SSLWrap<TLSWrap>;

src/node_crypto.h

@@ -63,8 +63,6 @@ enum CheckResult {
 
 extern int VerifyCallback(int preverify_ok, X509_STORE_CTX* ctx);
 
-extern X509_STORE* root_cert_store;
-
 extern void UseExtraCaCerts(const std::string& file);
 
 // Forward declaration