Cross compiling OSX on Linux

Cross compiling for OSX on Linux

Requirements

What you'll need:

[1] an Intel Mac running Leopard, Snow Leopard, or Lion

[2] XCode installed on your Mac or the original or retail OSX DVD (for the SDK)

[3] a working linux setup (Debian Squeeze in my case)

[4] up to date source for FPC (2.4.x) and Lazarus (0.9.30)

[5] the Open Darwin cctools (odcctools)

Once set up, you won't need the Mac to compile your code.

Copy SDK

STEP 1: copy the SDK from your Mac. You need to install XCode from your OSX DVD if you've not already done so and copy the SDK to an appropriate location on your Linux box. I'd recommend MacOSX10.5.sdk (compatible with Leopard) but it depends on how far back you want to be compatible. MacOSX10.5.sdk is located in /Developer/SDKs on the Mac. I put mine at /opt/MacOSX10.5.sdk on my Debian box. Example using ssh to copy over the files:

su - #become root
cd /opt
#regular users should have read access to /Developer/SDKs...
scp -r appleuser@applehostname:/Developer/SDKs/MacOSX10.5.sdk /opt/ #copy recursively, you might need to accept a key
#this will take a while, as the directory contains multiple gigabytes.

Get odcctools

STEP 2: grab odcctools from SVN (I use mercurial, hence the "hg" stuff) Install Mercurial if you haven't already:

aptitude install mercurial
mkdir ~/hg #store our hg repositories here, change according to taste
cd ~/hg
hg clone http://svn.macosforge.org/repository/odcctools/trunk/ odcctools

and build it as

cd ~/hg/odcctools && ./extract.sh && cd odcctools
CC=gcc-4.4 ./configure --target=i386-darwin \
 --prefix=/opt/odcctools --with-sysroot=/opt/MacOSX10.5.sdk
make && make install

I've specified gcc 4.4 but it should be okay with other versions.

Rebuild FPC

STEP 3: rebuild FPC (my sources are in ~/hg/pascal)

cd ~/hg/pascal && hg id -bint
 730fd5ffbeb1 16666 fixes_2_4 release_2_4_2
make distclean && FPC=ppc386 make crossall crossinstall \
 CPU_TARGET=i386 OS_TARGET=darwin \
 CROSSBINDIR=/opt/odcctools/bin BINUTILSPREFIX=i386-darwin- \
 INSTALL_PREFIX=/opt/cross \
 OPT="-gl -gw -godwarfsets -XX -CX -Xd -Fl/opt/MacOSX10.5.sdk/usr/lib"

Note that the options (OPT) as shown are vital, especially -gw.

STEP 4: add a darwin (cross-compile) clause to /etc/fpc.cfg

#IFDEF darwin
-Fu/opt/cross/lib/fpc/$fpcversion/units/i386-darwin/
-Fu/opt/cross/lib/fpc/$fpcversion/units/i386-darwin/*
-Fu/opt/cross/lib/fpc/$fpcversion/units/i386-darwin/rtl
-FD/opt/odcctools/bin
#ENDIF

Build Carbon LCL

STEP 5: build the Carbon LCL (in Lazarus)

Be sure to specify the Darwin OS target, i386 CPU target and, most importantly, add the -gw option. Perform a Clean+Build of the LCL and the Package Registration.

You should now be able to use Lazarus in Linux to build for Mac OSX.

Gotcha's

There are two more gotcha's when cross-compiling to OS X:

First, be sure to specify the -gw in your projects to avoid problems reported in (the unfixable) FPC bug #12001.

Second, be sure to specify the -XR option pointing to your SDK root, in my case -XR/opt/MacOSX10.5.sdk, or the Darwin linker will try to link to the wrong startup object (/usr/lib/crt1.o).

Source

Fpc Mailing list 6 August 2011 post by Bruce titled "Re: Cross Compiling from Linux to a Mac OS X 10.5 or 10.6 target. How? [SOLVED]" Adapted by BigChimp