The same error has affected all sketches that use #include<wifi.h>. Compiling the Arduino example ESP32 Async UDP - AsyncUDPClient (changed only to reflect local ssid & password) produced the following errors. Error messages point to ssl_ client.cpp. Plan to use Node32s board but errors occur before board is flashed. Used lArduino-esp32-master.zip ibraries dated 8/12/2018 & 9/10/2018 with same results
C:\Users\btuzin\AppData\Local\Temp\arduino_cache_29183 -prefs=build.warn_data_percentage=75 -verbose C:\Users\btuzin\AppData\Local\Temp\arduino_modified_sketch_124683\AsyncUDPClient.ino
.......LOTS OF VERBOSE MESSAGES......
IC:\Users\btuzin\Documents\Arduino\hardware\espressif\esp32/tools/sdk/include/wpa_supplicant" -std=gnu++11 -fno-exceptions -Os -g3 -Wpointer-arith -fexceptions -fstack-protector -ffunction-sections -fdata-sections -fstrict-volatile-bitfields -mlongcalls -nostdlib -Wall -Werror=all -Wno-error=unused-function -Wno-error=unused-but-set-variable -Wno-error=unused-variable -Wno-error=deprecated-declarations -Wno-unused-parameter -Wno-sign-compare -fno-rtti -MMD -c -DF_CPU=240000000L -DARDUINO=10806 -DARDUINO_Node32s -DARDUINO_ARCH_ESP32 "-DARDUINO_BOARD="Node32s"" "-DARDUINO_VARIANT="node32s"" -DESP32 -DCORE_DEBUG_LEVEL=0 "-IC:\Users\btuzin\Documents\Arduino\hardware\espressif\esp32\cores\esp32" "-IC:\Users\btuzin\Documents\Arduino\hardware\espressif\esp32\variants\node32s" "-IC:\Users\btuzin\Documents\Arduino\hardware\espressif\esp32\libraries\WiFi\src" "-IC:\Users\btuzin\Documents\Arduino\hardware\espressif\esp32\libraries\AsyncUDP\src" "-IC:\Users\btuzin\Documents\Arduino\hardware\espressif\esp32\libraries\WiFiClientSecure\src" "C:\Users\btuzin\Documents\Arduino\hardware\espressif\esp32\libraries\WiFi\src\sendemail.cpp" -o "C:\Users\btuzin\AppData\Local\Temp\arduino_build_266301\libraries\WiFi\sendemail.cpp.o"
C:\Users\btuzin\Documents\Arduino\hardware\espressif\esp32\libraries\WiFi\src\WiFiMulti.cpp: In member function 'uint8_t WiFiMulti::run(uint32_t)':
C:\Users\btuzin\Documents\Arduino\hardware\espressif\esp32\libraries\WiFi\src\WiFiMulti.cpp:122:27: warning: variable 'mac' set but not used [-Wunused-but-set-variable]
uint8_t * mac;
^
C:\Users\btuzin\Documents\Arduino\hardware\espressif\esp32\libraries\WiFi\src\WiFiClient.cpp: In member function 'virtual uint8_t WiFiClient::connected()':
C:\Users\btuzin\Documents\Arduino\hardware\espressif\esp32\libraries\WiFi\src\WiFiClient.cpp:440:13: warning: unused variable 'res' [-Wunused-variable]
int res = recv(fd(), &dummy, 0, MSG_DONTWAIT);
^
C:\Users\btuzin\Documents\Arduino\hardware\espressif\esp32\libraries\WiFi\src\WiFiSTA.cpp: In static member function 'static void WiFiSTAClass::_smartConfigCallback(uint32_t, void*)':
C:\Users\btuzin\Documents\Arduino\hardware\espressif\esp32\libraries\WiFi\src\WiFiSTA.cpp:686:30: warning: unused variable 'type' [-Wunused-variable]
smartconfig_type_t * type = (smartconfig_type_t *)result;
^
C:\Users\btuzin\Documents\Arduino\hardware\espressif\esp32\libraries\WiFi\src\WiFiSTA.cpp:697:26: warning: unused variable 'ip' [-Wunused-variable]
ip4_addr_t * ip = (ip4_addr_t *)result;
^
Compiling library "AsyncUDP"
"C:\Users\btuzin\Documents\Arduino\hardware\espressif\esp32/tools/xtensa-esp32-elf/bin/xtensa-esp32-elf-g++" -DESP_PLATFORM "-DMBEDTLS_CONFIG_FILE="mbedtls/esp_config.h"" -DHAVE_CONFIG_H "-
.......LOTS OF VERBOSE MESSAGES......
IC:\Users\btuzin\Documents\Arduino\hardware\espressif\esp32/tools/sdk/include/wpa_supplicant" -std=gnu++11 -fno-exceptions -Os -g3 -Wpointer-arith -fexceptions -fstack-protector -ffunction-sections -fdata-sections -fstrict-volatile-bitfields -mlongcalls -nostdlib -Wall -Werror=all -Wno-error=unused-function -Wno-error=unused-but-set-variable -Wno-error=unused-variable -Wno-error=deprecated-declarations -Wno-unused-parameter -Wno-sign-compare -fno-rtti -MMD -c -DF_CPU=240000000L -DARDUINO=10806 -DARDUINO_Node32s -DARDUINO_ARCH_ESP32 "-DARDUINO_BOARD="Node32s"" "-DARDUINO_VARIANT="node32s"" -DESP32 -DCORE_DEBUG_LEVEL=0 "-IC:\Users\btuzin\Documents\Arduino\hardware\espressif\esp32\cores\esp32" "-IC:\Users\btuzin\Documents\Arduino\hardware\espressif\esp32\variants\node32s" "-IC:\Users\btuzin\Documents\Arduino\hardware\espressif\esp32\libraries\WiFi\src" "-IC:\Users\btuzin\Documents\Arduino\hardware\espressif\esp32\libraries\AsyncUDP\src" "-IC:\Users\btuzin\Documents\Arduino\hardware\espressif\esp32\libraries\WiFiClientSecure\src" "C:\Users\btuzin\Documents\Arduino\hardware\espressif\esp32\libraries\WiFiClientSecure\src\WiFiClientSecure.cpp" -o "C:\Users\btuzin\AppData\Local\Temp\arduino_build_266301\libraries\WiFiClientSecure\WiFiClientSecure.cpp.o"
C:\Users\btuzin\Documents\Arduino\hardware\espressif\esp32\libraries\WiFiClientSecure\src\ssl_client.cpp: In function 'bool verify_ssl_dn(sslclient_context*, const char*)':
C:\Users\btuzin\Documents\Arduino\hardware\espressif\esp32\libraries\WiFiClientSecure\src\ssl_client.cpp:367:5: error: 'transform' is not a member of 'std'
std::transform(domain_name_str.begin(), domain_name_str.end(), domain_name_str.begin(), ::tolower);
^
C:\Users\btuzin\Documents\Arduino\hardware\espressif\esp32\libraries\WiFiClientSecure\src\ssl_client.cpp:377:9: error: 'transform' is not a member of 'std'
std::transform(san_str.begin(), san_str.end(), san_str.begin(), ::tolower);
^
Multiple libraries were found for "WiFi.h"
Used: C:\Users\btuzin\Documents\Arduino\hardware\espressif\esp32\libraries\WiFi
Not used: C:\Program Files\WindowsApps\ArduinoLLC.ArduinoIDE_1.8.14.0_x86__mdqgnx93n4wtt\libraries\WiFi
Using library WiFi at version 1.0 in folder: C:\Users\btuzin\Documents\Arduino\hardware\espressif\esp32\libraries\WiFi
Using library AsyncUDP at version 1.0.0 in folder: C:\Users\btuzin\Documents\Arduino\hardware\espressif\esp32\libraries\AsyncUDP
Using library WiFiClientSecure at version 1.0 in folder: C:\Users\btuzin\Documents\Arduino\hardware\espressif\esp32\libraries\WiFiClientSecure
exit status 1
Error compiling for board Node32s.