Something goes wrong with compiling ios if use_jumbo_build=true:

export DEVELOPER_DIR=/b/build/slave/ios-simulator/build/src/build/ios_files/Xcode.app;  TOOL_VERSION=1506020353 ../../build/toolchain/mac/linker_driver.py ../../third_party/llvm-build/Release+Asserts/bin/clang++  -Xlinker -rpath -Xlinker @executable_path/Frameworks -Xlinker -objc_abi_version -Xlinker 2 -Xlinker -sectcreate -Xlinker __TEXT -Xlinker __entitlements -Xlinker obj/base/base_i18n_perftests.xcent -arch x86_64 -Werror -isysroot /b/build/slave/ios-simulator/build/src/build/ios_files/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator11.0.sdk -stdlib=libc++ -mios-simulator-version-min=9.0 -Wl,-ObjC -o "obj/base/x64/base_i18n_perftests" -Wl,-filelist,"obj/base/x64/base_i18n_perftests.rsp"  -framework UIKit -framework CoreFoundation -framework CoreGraphics -framework CoreText -framework Foundation
Undefined symbols for architecture x86_64:
  "base::allocator::g_replaced_default_zone", referenced from:
      base::allocator::IsAllocatorInitialized() in libbase.a(base_jumbo_1.o)
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

It is similar to the problems with nacl in base. There is probably something with how allocators should be handled that is done wrong, but I am not sure what.

For nacl I just added a never_build_jumbo=true since nobody (?) outside Google build nacl anyway, but ios is potentially more widely used.