diff --git a/ext/mysql2/client.c b/ext/mysql2/client.c
index 5d75304b4..0b03372df 100644
--- a/ext/mysql2/client.c
+++ b/ext/mysql2/client.c
@@ -794,10 +794,12 @@ static VALUE _mysql_client_options(VALUE self, int opt, VALUE value) {
       retval = &boolval;
       break;
 
+#if defined(MYSQL_SECURE_AUTH)
     case MYSQL_SECURE_AUTH:
       boolval = (value == Qfalse ? 0 : 1);
       retval = &boolval;
       break;
+#endif
 
     case MYSQL_READ_DEFAULT_FILE:
       charval = (const char *)StringValueCStr(value);
@@ -1182,7 +1184,10 @@ static VALUE set_ssl_options(VALUE self, VALUE key, VALUE cert, VALUE ca, VALUE
 }
 
 static VALUE set_secure_auth(VALUE self, VALUE value) {
+/* This option was deprecated in MySQL 5.x and removed in MySQL 8.0 */
+#if defined(MYSQL_SECURE_AUTH)
   return _mysql_client_options(self, MYSQL_SECURE_AUTH, value);
+#endif
 }
 
 static VALUE set_read_default_file(VALUE self, VALUE value) {
@@ -1210,6 +1215,7 @@ static VALUE initialize_ext(VALUE self) {
 }
 
 void init_mysql2_client() {
+#ifdef _WIN32
   /* verify the libmysql we're about to use was the version we were built against
      https://github.com/luislavena/mysql-gem/commit/a600a9c459597da0712f70f43736e24b484f8a99 */
   int i;
@@ -1227,6 +1233,7 @@ void init_mysql2_client() {
       return;
     }
   }
+#endif
 
   /* Initializing mysql library, so different threads could call Client.new */
   /* without race condition in the library */
@@ -1297,6 +1304,10 @@ void init_mysql2_client() {
 #ifdef CLIENT_LONG_PASSWORD
   rb_const_set(cMysql2Client, rb_intern("LONG_PASSWORD"),
       LONG2NUM(CLIENT_LONG_PASSWORD));
+#else
+  /* HACK because MariaDB 10.2 no longer defines this constant,
+   * but we're using it in our default connection flags. */
+  rb_const_set(cMysql2Client, rb_intern("LONG_PASSWORD"), INT2NUM(0));
 #endif
 
 #ifdef CLIENT_FOUND_ROWS
diff --git a/ext/mysql2/extconf.rb b/ext/mysql2/extconf.rb
index 8590da386..3d1d75b2b 100644
--- a/ext/mysql2/extconf.rb
+++ b/ext/mysql2/extconf.rb
@@ -111,6 +111,12 @@ def asplode lib
   $CFLAGS << gcc_flags
 end
 
+mysql_h = [prefix, 'mysql.h'].compact.join('/')
+
+# my_bool is replaced by C99 bool in MySQL 8.0, but we want
+# to retain compatibility with the typedef in earlier MySQLs.
+have_type('my_bool', mysql_h)
+
 if RUBY_PLATFORM =~ /mswin|mingw/
   # Build libmysql.a interface link library
   require 'rake'
diff --git a/ext/mysql2/mysql2_ext.h b/ext/mysql2/mysql2_ext.h
index d6d5fd626..7d68ef5ba 100644
--- a/ext/mysql2/mysql2_ext.h
+++ b/ext/mysql2/mysql2_ext.h
@@ -38,6 +38,14 @@ typedef unsigned int    uint;
 #define RB_MYSQL_UNUSED
 #endif
 
+/* MySQL 8.0 replaces my_bool with C99 bool. Earlier versions of MySQL had
+ * a typedef to char. Gem users reported failures on big endian systems when
+ * using C99 bool types with older MySQLs due to mismatched behavior. */
+#ifndef HAVE_TYPE_MY_BOOL
+#include <stdbool.h>
+typedef bool my_bool;
+#endif
+
 #include <client.h>
 #include <result.h>
 #include <infile.h>