Fix conflict when both hiredis-rb and redis-client are loaded

ext/redis_client/hiredis/export.clang

@@ -0,0 +1,2 @@
+_Init_hiredis_connection
+_ruby_abi_version

ext/redis_client/hiredis/export.gcc

@@ -0,0 +1,7 @@
+hiredis_connection_1.0 { 
+ global: 
+ Init_hiredis_connection;
+ ruby_abi_version;
+ local: 
+ *;
+};

ext/redis_client/hiredis/extconf.rb

@@ -39,10 +39,18 @@
  end
 
  $CFLAGS << " -I#{hiredis_dir}"
- $LDFLAGS << " #{hiredis_dir}/libhiredis.a #{hiredis_dir}/libhiredis_ssl.a -lssl -lcrypto"
+ $LDFLAGS << " -lssl -lcrypto"
+ $libs << " #{hiredis_dir}/libhiredis.a #{hiredis_dir}/libhiredis_ssl.a "
  $CFLAGS << " -O3"
  $CFLAGS << " -std=c99 "
 
+ case RbConfig::CONFIG['CC']
+ when /gcc/i
+ $LDFLAGS << ' -Wl,--version-script="' << File.join(__dir__, 'export.gcc') << '"'
+ when /clang/i
+ $LDFLAGS << ' -Wl,-exported_symbols_list,"' << File.join(__dir__, 'export.clang') << '"'
+ end
+
  if ENV["EXT_PEDANTIC"]
  $CFLAGS << " -Werror"
  end

test/test_helper.rb

@@ -14,3 +14,12 @@
 unless ENV["REDIS_CLIENT_RESTART_SERVER"] == "0"
  Minitest.after_run { Servers::ALL.shutdown }
 end
+
+if ENV["DRIVER"] == "hiredis"
+ # See: https://github.com/redis-rb/redis-client/issues/16
+ # The hiredis-rb gems expose all hiredis symbols, so we must be careful
+ # about how we link against it.
+ require "redis"
+ require "hiredis"
+ Redis.new(host: Servers::HOST, port: Servers::REDIS_TCP_PORT, driver: :hiredis).ping
+end