GearVR export fails with Online Subsystem Oculus plugin enabled

I finally got around to testing some of the Online Subsystem features offered by the Oculus platform but I'm able to get an export to build with that plugin enabled using 4.15 from the Oculus github branch: https://github.com/Oculus-VR/UnrealEngine

Here's the error in the log:

UATHelper: Packaging (Android (ETC2)): UnrealBuildTool: [1/3] clang++.exe Module.OnlineSubsystemOculus.cpp [armv7-es2]
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool: In file included from U:/UnrealEngine/GitHub/UnrealEngine-4.15-oculus/Engine/Plugins/Online/OnlineSubsystemOculus/Intermediate/Build/Android/GC/Development/OnlineSubsystemOculus/Module.OnlineSubsystemOculus.cpp:14:
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool: U:\UnrealEngine\GitHub\UnrealEngine-4.15-oculus\Engine\Plugins\Online\OnlineSubsystemOculus\Source\Private\OnlineSessionInterfaceOculus.cpp(343,9) :  warning: declaration shadows a local variable [-Wshadow]
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool:                         auto Session = GetNamedSession(SessionName);
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool:                              ^
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool: U:\UnrealEngine\GitHub\UnrealEngine-4.15-oculus\Engine\Plugins\Online\OnlineSubsystemOculus\Source\Private\OnlineSessionInterfaceOculus.cpp(315,7) :  note: previous declaration is here
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool:         auto Session = GetNamedSession(SessionName);
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool:              ^
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool: U:\UnrealEngine\GitHub\UnrealEngine-4.15-oculus\Engine\Plugins\Online\OnlineSubsystemOculus\Source\Private\OnlineSessionInterfaceOculus.cpp(389,45) :  error: use of undeclared identifier '_strdup'; did you mean 'strdup'?
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool:                         DataStore.Add(ovrKeyValuePair_makeString(_strdup(Key.c_str()), _strdup(Value.c_str())));
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool:                                                                  ^~~~~~~
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool:                                                                  strdup
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool: U:/NVPACK/android-ndk-r12b/platforms/android-19/arch-arm/usr/include\string.h(59,15) :  note: 'strdup' declared here
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool: extern char*  strdup(const char *);
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool:               ^
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool: In file included from U:/UnrealEngine/GitHub/UnrealEngine-4.15-oculus/Engine/Plugins/Online/OnlineSubsystemOculus/Intermediate/Build/Android/GC/Development/OnlineSubsystemOculus/Module.OnlineSubsystemOculus.cpp:14:
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool: U:\UnrealEngine\GitHub\UnrealEngine-4.15-oculus\Engine\Plugins\Online\OnlineSubsystemOculus\Source\Private\OnlineSessionInterfaceOculus.cpp(389,67) :  error: use of undeclared identifier '_strdup'; did you mean 'strdup'?
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool:                         DataStore.Add(ovrKeyValuePair_makeString(_strdup(Key.c_str()), _strdup(Value.c_str())));
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool:                                                                                        ^~~~~~~
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool:                                                                                        strdup
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool: U:/NVPACK/android-ndk-r12b/platforms/android-19/arch-arm/usr/include\string.h(59,15) :  note: 'strdup' declared here
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool: extern char*  strdup(const char *);
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool:               ^
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool: In file included from U:/UnrealEngine/GitHub/UnrealEngine-4.15-oculus/Engine/Plugins/Online/OnlineSubsystemOculus/Intermediate/Build/Android/GC/Development/OnlineSubsystemOculus/Module.OnlineSubsystemOculus.cpp:14:
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool: U:\UnrealEngine\GitHub\UnrealEngine-4.15-oculus\Engine\Plugins\Online\OnlineSubsystemOculus\Source\Private\OnlineSessionInterfaceOculus.cpp(406,45) :  error: use of undeclared identifier '_strdup'; did you mean 'strdup'?
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool:                         DataStore.Add(ovrKeyValuePair_makeString(_strdup(Key.c_str()), ""));
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool:                                                                  ^~~~~~~
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool:                                                                  strdup
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool: U:/NVPACK/android-ndk-r12b/platforms/android-19/arch-arm/usr/include\string.h(59,15) :  note: 'strdup' declared here
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool: extern char*  strdup(const char *);
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool:               ^
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool: In file included from U:/UnrealEngine/GitHub/UnrealEngine-4.15-oculus/Engine/Plugins/Online/OnlineSubsystemOculus/Intermediate/Build/Android/GC/Development/OnlineSubsystemOculus/Module.OnlineSubsystemOculus.cpp:14:
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool: U:\UnrealEngine\GitHub\UnrealEngine-4.15-oculus\Engine\Plugins\Online\OnlineSubsystemOculus\Source\Private\OnlineSessionInterfaceOculus.cpp(433,9) :  warning: declaration shadows a local variable [-Wshadow]
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool:                         auto Session = GetNamedSession(SessionName);
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool:                              ^
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool: U:\UnrealEngine\GitHub\UnrealEngine-4.15-oculus\Engine\Plugins\Online\OnlineSubsystemOculus\Source\Private\OnlineSessionInterfaceOculus.cpp(367,7) :  note: previous declaration is here
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool:         auto Session = GetNamedSession(SessionName);
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool:              ^
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool: U:\UnrealEngine\GitHub\UnrealEngine-4.15-oculus\Engine\Plugins\Online\OnlineSubsystemOculus\Source\Private\OnlineSessionInterfaceOculus.cpp(1314,30) :  error: no member named 'stoi' in namespace 'std'; did you mean 'atoi'?
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool:                         int32 IntDataStoreValue = std::stoi(DataStoreValue);
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool:                                                   ^~~~~~~~~
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool:                                                   atoi
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool: U:/NVPACK/android-ndk-r12b/platforms/android-19/arch-arm/usr/include\stdlib.h(79,12) :  note: 'atoi' declared here
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool: extern int atoi(const char *);
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool:            ^
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool: 2 warnings and 4 errors generated.
UATHelper: Packaging (Android (ETC2)): UnrealBuildTool: ERROR: UBT ERROR: Failed to produce item: U:\UnrealEngine\GitHub\UnrealEngine-4.15-oculus\Engine\Plugins\Online\OnlineSubsystemOculus\Binaries\Android\GC-OnlineSubsystemOculus-armv7-es2.a

Any ideas what I'm doing wrong? Is this plugin now supported for gearvr?