Google Protobuf v2.6.0 Build Script for iOS

.gitignore

protobuf
protobuf-2.6.0
protobuf-2.6.1
protobuf-master

README.md

Google Protobuf - Mac OS X and iOS Support

The script in this gist will help you buid the Google Protobuf library for use with Mac OS X and iOS. Other methods (such as homebrew or direct compilation) have issues that prevent their use. The libraries built by this script are universal and support all iOS device architectures including the simluator.

Get the Script

The easiest way to use this script is to simply clone the gist onto your machine using the following command:

$ git clone https://gist.github.com/9487468ae3375d0db0cc.git build-protobuf

Performing the Build

The script will automatically download the tarball from Google Code, so all you need to do is run the script. This will build the 2.6.1 version of Protobuf. The script understands a few command-line options too.

$ cd build-protobuf
$ ./build-protobuf.sh

Add --interactive to the above script if you would like the script to stop after each major operation. This makes it easier to inspect the output from the various steps for potential errors.

Add --master if you would prefer to build from the master branch in the Google Protobuf git repo.

Results

Build results are found in a folder called protobuf-{version}, where {version} will be either 2.6.1 or master. This folder contains bin, include and lib folders.

Integration with Xcode

Create a build rule in your Xcode project with the following settings.

Process *Source files with names matching:* `*.proto`
Using *Custom script:*

cd ${INPUT_FILE_DIR}
${SRCROOT}/Google/protobuf/bin/protoc --proto_path=${INPUT_FILE_DIR} ${INPUT_FILE_PATH} --cpp_out=${DERIVED_FILE_DIR}

Output Files
$(DERIVED_FILE_DIR)/$(INPUT_FILE_BASE).pb.cc
$(DERIVED_FILE_DIR)/$(INPUT_FILE_BASE).pb.h

Depending on where you choose to install the protobuf build, you will need to adjust the path to protoc.

FAQ

Can Protobuf be built using libstdc++?

Unfortunately, the protobuf C++ code is not compatible with libstdc++ at the moment. You must use libc++ instead.

Can you provide a similar script for Android?

No

Why am I gettings all the implicit conversion looses integer precision warnings?

Unfortunately, the code generated by protoc is not 64-bit clean. In practice I have not experienced any issues as a result of this. It would be better if the generated code was reworked for better 64-bit support. This may come with the 3.0 version they are working on now.

build-protobuf.sh

#!/bin/bash

echo "$(tput setaf 2)"
echo "###################################################################"
echo "# Preparing to build Google Protobuf"
echo "###################################################################"
echo "$(tput sgr0)"

# The version of Protobuf to build.  It must match
# one of the values found in the releases section of the github repo.
# It can be set to "master" when building directly from the github repo.
PROTOBUF_VERSION=2.6.1

# Set to "YES" if you would like the build script to
# pause after each major section.
INTERACTIVE=NO

# A "YES" value will build the latest code from GitHub on the master branch.
# A "NO" value will use the 2.6.1 tarball downloaded from googlecode.com.
USE_GIT_MASTER=NO

while [[ $# > 0 ]]
do
  key="$1"

  case $key in
    -i|--interactive)
      INTERACTIVE=YES
      ;;
    -m|--master)
      USE_GIT_MASTER=YES
      PROTOBUF_VERSION=master
      ;;
    *)
      # unknown option
      ;;
  esac
  shift # past argument or value
done

function conditionalPause {
  if [ "${INTERACTIVE}"  == "YES" ]
  then
    while true; do
        read -p "Proceed with build? (y/n) " yn
        case $yn in
            [Yy]* ) break;;
            [Nn]* ) exit;;
            * ) echo "Please answer yes or no.";;
        esac
    done
  fi
}

# The results will be stored relative to the location
# where you stored this script, **not** relative to
# the location of the protobuf git repo.
PREFIX=`pwd`/protobuf
if [ -d ${PREFIX} ]
then
    rm -rf "${PREFIX}"
fi
mkdir -p "${PREFIX}/platform"

PROTOBUF_GIT_URL=https://github.com/google/protobuf.git
PROTOBUF_GIT_DIRNAME=protobuf
PROTOBUF_RELEASE_URL=https://github.com/google/protobuf/releases/download/v${PROTOBUF_VERSION}/protobuf-${PROTOBUF_VERSION}.tar.gz
PROTOBUF_RELEASE_DIRNAME=protobuf-${PROTOBUF_VERSION}

BUILD_MACOSX_X86_64=YES

BUILD_I386_IOSSIM=YES
BUILD_X86_64_IOSSIM=YES

BUILD_IOS_ARMV7=YES
BUILD_IOS_ARMV7S=YES
BUILD_IOS_ARM64=YES

PROTOBUF_SRC_DIR=/tmp/protobuf

# 13.4.0 - Mavericks
# 14.0.0 - Yosemite
# 15.0.0 - El Capitan
DARWIN=darwin14.0.0

XCODEDIR=`xcode-select --print-path`
IOS_SDK_VERSION=`xcrun --sdk iphoneos --show-sdk-version`
MIN_SDK_VERSION=8.3

MACOSX_PLATFORM=${XCODEDIR}/Platforms/MacOSX.platform
MACOSX_SYSROOT=${MACOSX_PLATFORM}/Developer/MacOSX10.9.sdk

IPHONEOS_PLATFORM=`xcrun --sdk iphoneos --show-sdk-platform-path`
IPHONEOS_SYSROOT=`xcrun --sdk iphoneos --show-sdk-path`

IPHONESIMULATOR_PLATFORM=`xcrun --sdk iphonesimulator --show-sdk-platform-path`
IPHONESIMULATOR_SYSROOT=`xcrun --sdk iphonesimulator --show-sdk-path`

# Uncomment if you want to see more information about each invocation
# of clang as the builds proceed.
# CLANG_VERBOSE="--verbose"

CC=clang
CXX=clang

SILENCED_WARNINGS="-Wno-unused-local-typedef -Wno-unused-function"

# NOTE: Google Protobuf does not currently build if you specify 'libstdc++'
# instead of `libc++` here.
STDLIB=libc++

CFLAGS="${CLANG_VERBOSE} ${SILENCED_WARNINGS} -DNDEBUG -g -O0 -pipe -fPIC -fcxx-exceptions"
CXXFLAGS="${CLANG_VERBOSE} ${CFLAGS} -std=c++11 -stdlib=${STDLIB}"

LDFLAGS="-stdlib=${STDLIB}"
LIBS="-lc++ -lc++abi"

echo "PREFIX ..................... ${PREFIX}"
echo "USE_GIT_MASTER ............. ${USE_GIT_MASTER}"
echo "PROTOBUF_GIT_URL ........... ${PROTOBUF_GIT_URL}"
echo "PROTOBUF_GIT_DIRNAME ....... ${PROTOBUF_GIT_DIRNAME}"
echo "PROTOBUF_VERSION ........... ${PROTOBUF_VERSION}"
echo "PROTOBUF_RELEASE_URL ....... ${PROTOBUF_RELEASE_URL}"
echo "PROTOBUF_RELEASE_DIRNAME ... ${PROTOBUF_RELEASE_DIRNAME}"
echo "BUILD_MACOSX_X86_64 ........ ${BUILD_MACOSX_X86_64}"
echo "BUILD_I386_IOSSIM .......... ${BUILD_I386_IOSSIM}"
echo "BUILD_X86_64_IOSSIM ........ ${BUILD_X86_64_IOSSIM}"
echo "BUILD_IOS_ARMV7 ............ ${BUILD_IOS_ARMV7}"
echo "BUILD_IOS_ARMV7S ........... ${BUILD_IOS_ARMV7S}"
echo "BUILD_IOS_ARM64 ............ ${BUILD_IOS_ARM64}"
echo "PROTOBUF_SRC_DIR ........... ${PROTOBUF_SRC_DIR}"
echo "DARWIN ..................... ${DARWIN}"
echo "XCODEDIR ................... ${XCODEDIR}"
echo "IOS_SDK_VERSION ............ ${IOS_SDK_VERSION}"
echo "MIN_SDK_VERSION ............ ${MIN_SDK_VERSION}"
echo "MACOSX_PLATFORM ............ ${MACOSX_PLATFORM}"
echo "MACOSX_SYSROOT ............. ${MACOSX_SYSROOT}"
echo "IPHONEOS_PLATFORM .......... ${IPHONEOS_PLATFORM}"
echo "IPHONEOS_SYSROOT ........... ${IPHONEOS_SYSROOT}"
echo "IPHONESIMULATOR_PLATFORM ... ${IPHONESIMULATOR_PLATFORM}"
echo "IPHONESIMULATOR_SYSROOT .... ${IPHONESIMULATOR_SYSROOT}"
echo "CC ......................... ${CC}"
echo "CFLAGS ..................... ${CFLAGS}"
echo "CXX ........................ ${CXX}"
echo "CXXFLAGS ................... ${CXXFLAGS}"
echo "LDFLAGS .................... ${LDFLAGS}"
echo "LIBS ....................... ${LIBS}"

conditionalPause

echo "$(tput setaf 2)"
echo "###################################################################"
echo "# Fetch Google Protobuf"
echo "###################################################################"
echo "$(tput sgr0)"

(
    if [ -d ${PROTOBUF_SRC_DIR} ]
    then
        rm -rf ${PROTOBUF_SRC_DIR}
    fi

    cd `dirname ${PROTOBUF_SRC_DIR}`

    if [ "${USE_GIT_MASTER}" == "YES" ]
    then
        git clone ${PROTOBUF_GIT_URL}
    else
        if [ -d ${PROTOBUF_RELEASE_DIRNAME} ]
        then
            rm -rf "${PROTOBUF_RELEASE_DIRNAME}"
        fi
        curl --location ${PROTOBUF_RELEASE_URL} --output ${PROTOBUF_RELEASE_DIRNAME}.tar.gz
        tar xvf ${PROTOBUF_RELEASE_DIRNAME}.tar.gz
        mv "${PROTOBUF_RELEASE_DIRNAME}" "${PROTOBUF_SRC_DIR}"
        rm ${PROTOBUF_RELEASE_DIRNAME}.tar.gz

        # Remove the version of Google Test included with the release.
        # We will replace it with version 1.7.0 in a later step.
        if [ -d "${PROTOBUF_SRC_DIR}/gtest" ]
        then
            rm -r "${PROTOBUF_SRC_DIR}/gtest"
        fi
    fi
)

conditionalPause

if [ "${PROTOBUF_VERSION}" == "master" ]
then

  echo "$(tput setaf 2)"
  echo "###################################################################"
  echo "# Run autogen.sh to prepare for build."
  echo "###################################################################"
  echo "$(tput sgr0)"

  (
    cd ${PROTOBUF_SRC_DIR}
    ( exec ./autogen.sh )
  )

else

  echo "$(tput setaf 2)"
  echo "###################################################################"
  echo "# Fetch Google Test & Prepare the Configure Script"
  echo "#   (note: This section is lifted from autogen.sh)"
  echo "###################################################################"
  echo "$(tput sgr0)"

  (
      cd ${PROTOBUF_SRC_DIR}

      # Check that we are being run from the right directory.
      if test ! -f src/google/protobuf/stubs/common.h
      then
          cat >&2 << __EOF__
Could not find source code.  Make sure you are running this script from the
root of the distribution tree.
__EOF__
          exit 1
      fi

      # Check that gtest is present. Older versions of protobuf were stored in SVN
      # and the gtest directory was setup as an SVN external.  Now, protobuf is
      # stored in GitHub and the gtest directory is not included. The commands
      # below will grab the latest version of gtest. Currently that is 1.7.0.
      if test ! -e gtest
      then
          echo "Google Test not present.  Fetching gtest-1.7.0 from the web..."
          curl --location https://github.com/google/googletest/archive/release-1.7.0.tar.gz --output gtest-1.7.0.tar.gz
          tar xvf gtest-1.7.0.tar.gz
          rm gtest-1.7.0.tar.gz
          mv googletest-release-1.7.0 gtest
      fi

      autoreconf -f -i -Wall,no-obsolete
      rm -rf autom4te.cache config.h.in~
  )

fi

conditionalPause

###################################################################
# This section contains the build commands to create the native
# protobuf library for Mac OS X.  This is done first so we have
# a copy of the protoc compiler.  It will be used in all of the
# susequent iOS builds.
###################################################################

echo "$(tput setaf 2)"
echo "###################################################################"
echo "# x86_64 for Mac OS X"
echo "###################################################################"
echo "$(tput sgr0)"

if [ "${BUILD_MACOSX_X86_64}" == "YES" ]
then
    (
        cd ${PROTOBUF_SRC_DIR}
        make distclean
        ./configure --disable-shared --prefix=${PREFIX} --exec-prefix=${PREFIX}/platform/x86_64-mac "CC=${CC}" "CFLAGS=${CFLAGS} -arch x86_64" "CXX=${CXX}" "CXXFLAGS=${CXXFLAGS} -arch x86_64" "LDFLAGS=${LDFLAGS}" "LIBS=${LIBS}"
        make
        make check
        make install
    )
fi

PROTOC=${PREFIX}/platform/x86_64-mac/bin/protoc

conditionalPause

###################################################################
# This section contains the build commands for each of the 
# architectures that will be included in the universal binaries.
###################################################################

echo "$(tput setaf 2)"
echo "###########################"
echo "# i386 for iPhone Simulator"
echo "###########################"
echo "$(tput sgr0)"

if [ "${BUILD_I386_IOSSIM}" == "YES" ]
then
    (
        cd ${PROTOBUF_SRC_DIR}
        make distclean
        ./configure --build=x86_64-apple-${DARWIN} --host=i386-apple-${DARWIN} --with-protoc=${PROTOC} --disable-shared --prefix=${PREFIX} --exec-prefix=${PREFIX}/platform/i386-sim "CC=${CC}" "CFLAGS=${CFLAGS} -mios-simulator-version-min=${MIN_SDK_VERSION} -arch i386 -isysroot ${IPHONESIMULATOR_SYSROOT}" "CXX=${CXX}" "CXXFLAGS=${CXXFLAGS} -mios-simulator-version-min=${MIN_SDK_VERSION} -arch i386 -isysroot ${IPHONESIMULATOR_SYSROOT}" LDFLAGS="-arch i386 -mios-simulator-version-min=${MIN_SDK_VERSION} ${LDFLAGS} -L${IPHONESIMULATOR_SYSROOT}/usr/lib/ -L${IPHONESIMULATOR_SYSROOT}/usr/lib/system" "LIBS=${LIBS}"
        make
        make install
    )
fi

conditionalPause

echo "$(tput setaf 2)"
echo "#############################"
echo "# x86_64 for iPhone Simulator"
echo "#############################"
echo "$(tput sgr0)"

if [ "${BUILD_X86_64_IOSSIM}" == "YES" ]
then
    (
        cd ${PROTOBUF_SRC_DIR}
        make distclean
        ./configure --build=x86_64-apple-${DARWIN} --host=x86_64-apple-${DARWIN} --with-protoc=${PROTOC} --disable-shared --prefix=${PREFIX} --exec-prefix=${PREFIX}/platform/x86_64-sim "CC=${CC}" "CFLAGS=${CFLAGS} -mios-simulator-version-min=${MIN_SDK_VERSION} -arch x86_64 -isysroot ${IPHONESIMULATOR_SYSROOT}" "CXX=${CXX}" "CXXFLAGS=${CXXFLAGS} -mios-simulator-version-min=${MIN_SDK_VERSION} -arch x86_64 -isysroot ${IPHONESIMULATOR_SYSROOT}" LDFLAGS="-arch x86_64 -mios-simulator-version-min=${MIN_SDK_VERSION} ${LDFLAGS} -L${IPHONESIMULATOR_SYSROOT}/usr/lib/ -L${IPHONESIMULATOR_SYSROOT}/usr/lib/system" "LIBS=${LIBS}"
        make
        make install
    )
fi

conditionalPause

echo "$(tput setaf 2)"
echo "##################"
echo "# armv7 for iPhone"
echo "##################"
echo "$(tput sgr0)"

if [ "${BUILD_IOS_ARMV7}" == "YES" ]
then
    (
        cd ${PROTOBUF_SRC_DIR}
        make distclean
        ./configure --build=x86_64-apple-${DARWIN} --host=armv7-apple-${DARWIN} --with-protoc=${PROTOC} --disable-shared --prefix=${PREFIX} --exec-prefix=${PREFIX}/platform/armv7-ios "CC=${CC}" "CFLAGS=${CFLAGS} -miphoneos-version-min=${MIN_SDK_VERSION} -arch armv7 -isysroot ${IPHONEOS_SYSROOT}" "CXX=${CXX}" "CXXFLAGS=${CXXFLAGS} -arch armv7 -isysroot ${IPHONEOS_SYSROOT}" LDFLAGS="-arch armv7 -miphoneos-version-min=${MIN_SDK_VERSION} ${LDFLAGS}" "LIBS=${LIBS}"
        make
        make install
    )
fi

conditionalPause

echo "$(tput setaf 2)"
echo "###################"
echo "# armv7s for iPhone"
echo "###################"
echo "$(tput sgr0)"

if [ "${BUILD_IOS_ARMV7S}" == "YES" ]
then
    (
        cd ${PROTOBUF_SRC_DIR}
        make distclean
        ./configure --build=x86_64-apple-${DARWIN} --host=armv7s-apple-${DARWIN} --with-protoc=${PROTOC} --disable-shared --prefix=${PREFIX} --exec-prefix=${PREFIX}/platform/armv7s-ios "CC=${CC}" "CFLAGS=${CFLAGS} -miphoneos-version-min=${MIN_SDK_VERSION} -arch armv7s -isysroot ${IPHONEOS_SYSROOT}" "CXX=${CXX}" "CXXFLAGS=${CXXFLAGS} -miphoneos-version-min=${MIN_SDK_VERSION} -arch armv7s -isysroot ${IPHONEOS_SYSROOT}" LDFLAGS="-arch armv7s -miphoneos-version-min=${MIN_SDK_VERSION} ${LDFLAGS}" "LIBS=${LIBS}"
        make
        make install
    )
fi

conditionalPause

echo "$(tput setaf 2)"
echo "##################"
echo "# arm64 for iPhone"
echo "##################"
echo "$(tput sgr0)"

if [ "${BUILD_IOS_ARM64}" == "YES" ]
then
    (
        cd ${PROTOBUF_SRC_DIR}
        make distclean
        ./configure --build=x86_64-apple-${DARWIN} --host=arm --with-protoc=${PROTOC} --disable-shared --prefix=${PREFIX} --exec-prefix=${PREFIX}/platform/arm64-ios "CC=${CC}" "CFLAGS=${CFLAGS} -miphoneos-version-min=${MIN_SDK_VERSION} -arch arm64 -isysroot ${IPHONEOS_SYSROOT}" "CXX=${CXX}" "CXXFLAGS=${CXXFLAGS} -miphoneos-version-min=${MIN_SDK_VERSION} -arch arm64 -isysroot ${IPHONEOS_SYSROOT}" LDFLAGS="-arch arm64 -miphoneos-version-min=${MIN_SDK_VERSION} ${LDFLAGS}" "LIBS=${LIBS}"
        make
        make install
    )
fi

conditionalPause

echo "$(tput setaf 2)"
echo "###################################################################"
echo "# Create Universal Libraries and Finalize the packaging"
echo "###################################################################"
echo "$(tput sgr0)"

(
    cd ${PREFIX}/platform
    mkdir universal
    lipo x86_64-sim/lib/libprotobuf.a i386-sim/lib/libprotobuf.a arm64-ios/lib/libprotobuf.a armv7s-ios/lib/libprotobuf.a armv7-ios/lib/libprotobuf.a -create -output universal/libprotobuf.a
    lipo x86_64-sim/lib/libprotobuf-lite.a i386-sim/lib/libprotobuf-lite.a arm64-ios/lib/libprotobuf-lite.a armv7s-ios/lib/libprotobuf-lite.a armv7-ios/lib/libprotobuf-lite.a -create -output universal/libprotobuf-lite.a
)

(
    cd ${PREFIX}
    mkdir bin
    mkdir lib
    cp -r platform/x86_64-mac/bin/protoc bin
    cp -r platform/x86_64-mac/lib/* lib
    cp -r platform/universal/* lib
    rm -rf platform
    lipo -info lib/libprotobuf.a
    lipo -info lib/libprotobuf-lite.a
)

if [ "${USE_GIT_MASTER}" == "YES" ]
then
    if [ -d "${PREFIX}-master" ]
    then
        rm -rf "${PREFIX}-master"
    fi
    mv "${PREFIX}" "${PREFIX}-master"
else
    if [ -d "${PREFIX}-${PROTOBUF_VERSION}" ]
    then
        rm -rf "${PREFIX}-${PROTOBUF_VERSION}"
    fi
    mv "${PREFIX}" "${PREFIX}-${PROTOBUF_VERSION}"
fi

echo Done!

The script has bee updated to include changes from @Gubarev. I have also added support for building from the master branch of the Google Protobuf repo. This means you can now either build for 2.6.1 or the latest 3.x alpha. Both versions are maintained in separate folders relative to the script so you can give them both a try.

Thanks for the script. I'm seeing some linker warnings with Xcode 7.0:

ld: warning: object file (libprotobuf-lite.a(atomicops_internals_x86_gcc.o)) was built for newer iOS version (9.0) than being linked (8.0)

I've specified MIN_SDK_VERSION=8.0 in the script prior to building. Is there anything else I can do to make Xcode 7 happy?

Thanks @BennettSmith

linke error in Xcode 7
(linker command failed with exit code 1)

Solution is below
not include mac x86_64 library in universal
remove - cp -r platform/x86_64-mac/lib/* lib

Plus
If you want to build with libstdc++.
change compiler clang to gcc , g++

CC=gcc
CXX=g++
STDLIB=libstdc++

https://gist.github.com/ksc91u/bef7e2482018a5d363b8

• modified version to add -fembed-bitcode for iOS 9
• change lipo command, do not require all platforms to be built.

Using Xcode 7, I'm getting errors as reported by others, even with the latest version of this script:

building for iOS simulator, but linking in object file built for OSX, for architecture x86_64

I will try one of the forks out there.

There must be still some important differences between this script and the fork of it here:

https://gist.github.com/Gubarev/a5a56135c9ff814b0117

I was able to build and compile fine for iOS in Xcode 7 by linking to the library built with the fork, but not the one built with the script here.

Hi, I'm running the build script and getting this error when trying to create the universal lib:

###################################################################
# Create Universal Libraries and Finalize the packaging
###################################################################

fatal error: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/lipo: x86_64-sim/lib/libprotobuf.a and i386-sim/lib/libprotobuf.a have the same architectures (x86_64) and can't be in the same fat output file
fatal error: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/lipo: x86_64-sim/lib/libprotobuf-lite.a and i386-sim/lib/libprotobuf-lite.a have the same architectures (x86_64) and can't be in the same fat output file

Not sure why the x86_64 and the i386 libs have the same architecture, what am I missing?�

Thanks

I made one change to the script that seemed to resolve all my object file was built for newer iOS version linker warnings. You can check it out here: https://gist.github.com/robmaceachern/624633ff957cf147bfcd/revisions#diff-146617bd233bdd2215d983c3b57d62f2L329

I'm getting errors with lipo:

###################################################################

Create Universal Libraries and Finalize the packaging

###################################################################

fatal error: lipo: can't open input file: x86_64-sim/lib/libprotobuf.a (No such file or directory)
fatal error: lipo: can't open input file: x86_64-sim/lib/libprotobuf-lite.a (No such file or directory)
cp: platform/universal/*: No such file or directory
input file lib/libprotobuf.a is not a fat file
Non-fat file: lib/libprotobuf.a is architecture: x86_64
input file lib/libprotobuf-lite.a is not a fat file
Non-fat file: lib/libprotobuf-lite.a is architecture: x86_64
Done!

I am getting following error while running script compile_ios_protobuf.sh to make tensoflow for ios on a MacBook Pro,
Static Libraries for ios_arm64 ,ios_arm7,ios_arm7s,iossim_386 are getting compiled but iossim_x86_64 can't be built due to following error

===========================

checking whether we are cross compiling... configure: error: in ~/Tensorflow_on_ios/tensorflow-master/tensorflow/contrib/makefile/downloads/protobuf': configure: error: cannot run C compiled programs. If you meant to cross compile, use --host'.
See `config.log' for more details

• make
  make: *** No targets specified and no makefile found. Stop.
• make install
  make: *** No rule to make target `install'. Stop.
• make distclean
  make: *** No rule to make target `distclean'. Stop.

@nitinh @benstadin That is a problem with Sierra due to the compiler :( . Found a fix thanks to tensorflow/tensorflow#4640. Just remove the --build=x86_64-xxxx part from the x86_64 simulator. Or compile on < Sierra.

Just as a recommendation for anyone looking into building protobuf 3's, Google maintains TensorFlow, which has an iOS lib - and it uses Protobuf under the hood. So, if you build TensorFlow for iOS, you'll get the protobuf libraries for iOS....

Alternatively, this file should compile only the protobufs. https://github.com/tensorflow/tensorflow/blob/master/tensorflow/contrib/makefile/compile_ios_protobuf.sh