leptonica 1.69 crosscompile for iOS (armv7, armv7s and arm64)

Question

I try to cross compile leptonica 1.69 for armv7, armv7s and arm64.

For simulator (i386, x86_64) I use these settings and it works fine:

export IOS_BASE_SDK="7.1"
export IOS_DEPLOY_TGT="6.1"
export TOOLCHAIN=/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain 
export DEVROOT=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer

export SDKROOT=$DEVROOT/SDKs/iPhoneSimulator$IOS_BASE_SDK.sdk
export CFLAGS="-arch x86_64 -pipe -no-cpp-precomp -isysroot $SDKROOT -miphoneos-version-min=$IOS_DEPLOY_TGT -I$SDKROOT/usr/include/"

export CPP=$TOOLCHAIN/usr/bin/cpp
export CXX=$TOOLCHAIN/usr/bin/c++
export CXXCPP=$TOOLCHAIN/usr/bin/cpp
export CC=$TOOLCHAIN/usr/bin/cc
export LD=$TOOLCHAIN/usr/bin/ld
export AR=$TOOLCHAIN/usr/bin/ar
export AS=$TOOLCHAIN/usr/bin/as
export NM=$TOOLCHAIN/usr/bin/nm
export RANLIB=$TOOLCHAIN/usr/bin/ranlib
export LDFLAGS="-L$SDKROOT/usr/lib/"

export CPPFLAGS="-no-cpp-precomp -I$SDKROOT/usr/include/"
export CXXFLAGS=$CFLAGS

And then call configure

./configure --enable-shared=no --disable-programs --without-zlib --without-libpng --without-jpeg --without-giflib --without-libtiff --libdir=$PWD/lib/nodebug

Now to build it for arm I tried to use these settings: (adding -arch to CFLAGS and CPPFLAGS, setting the SDK root and adding --host=x86_64)

export DEVROOT=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer
export SDKROOT=$DEVROOT/SDKs/iPhoneOS$IOS_BASE_SDK.sdk
export CFLAGS="-arch armv7 -pipe -no-cpp-precomp -isysroot $SDKROOT -miphoneos-version-min=$IOS_DEPLOY_TGT -I$SDKROOT/usr/include/"
export CPPFLAGS="-arch armv7 -no-cpp-precomp -I$SDKROOT/usr/include/"

./configure --host=x86_64 --enable-shared=no --disable-programs --without-zlib --without-libpng --without-jpeg --without-giflib --without-libtiff --libdir=$PWD/lib/nodebug

but somehow the cpp does not work. The config logs says the following:

configure:5841: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/cpp -arch armv7 -no-cpp-precomp -I/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.1.sdk/usr/include/ conftest.c
clang: error: no input files

Anyone any ideas what's wrong? Or any idea how to debug this further?

Answer 1

It seems that something with my paths to the compiler, preprocessors etc was wrong. Using just the default ones in the path works. So removing the following part solved my issue:

export CPP=$TOOLCHAIN/usr/bin/cpp
export CXX=$TOOLCHAIN/usr/bin/c++
export CXXCPP=$TOOLCHAIN/usr/bin/cpp
export CC=$TOOLCHAIN/usr/bin/cc
export LD=$TOOLCHAIN/usr/bin/ld
export AR=$TOOLCHAIN/usr/bin/ar
export AS=$TOOLCHAIN/usr/bin/as
export NM=$TOOLCHAIN/usr/bin/nm
export RANLIB=$TOOLCHAIN/usr/bin/ranlib
export LDFLAGS="-L$SDKROOT/usr/lib/"