[fpc-pascal] Crosscompile linking problems

[Marco van de Voort]

> > > C:\FPC\2.0.0\lib\/libc.so: undefined reference to
> > > `_dl_lookup_versioned_symbol_skip at GLIBC_PRIVATE'
> > > C:\FPC\2.0.0\lib\/libpthread.so: undefined reference to
> > > `_rtld_global at GLIBC_PRIVATE'
> > > C:\FPC\2.0.0\lib\/libc.so: undefined reference to
> > > `_dl_lookup_versioned_symbol at GLIBC_PRIVATE'
> > > Have you some ideas? Have I missed somethink?
> > >
> > > I call it by commandline:
> > > fpc -Tlinux webtouch -XPi386-linux-
> > 
> > Looks like the dynamic linker loader (ld-linux.so) is missing
> 
> I have it in my lib directory... ld-linux.so and ld-linux.so.2 (copy 
> of ld-linux.so)

I compiled Lazarus from win32 to Linux/FreeBSD a while ago, here are my
summary notes:


To compile linux lazarus on windows: (the procedure from freebsd will not
differ much, the cprt0 copying is not needed for FreeBSD)

Requirements:
- FPC 1.9.6 or higher. 1.9.4 might work, but untested.
- ftp://freepascal.stack.nl/pub/fpc/contrib/cross/mingw/binutils-2.15-win32-i386-linux.zip
- A FPC CVS repository.  (anything 1.9.6+ that is buildable will do)
- a lazarus tree. (anything buildable from the same period will do)
- Lots of libraries from the target linux system. One of the FPC servers is some SUSE, 
    that's where I got the list below.

1) Download ftp://freepascal.stack.nl/pub/fpc/contrib/cross/mingw/binutils-2.15-win32-i386-linux.zip
2) extract it and move the i386* files to <fpcbindir>\bin\i386-win32  (e.g. c:\pp\bin\i386\win32)
3) enter FPC source dir
4) make clean 
5) make OS_TARGET=linux all
6) make OS_TARGET=linux install INSTALL_PREFIX=<fpcbindir>
7) prepare the lib directory as in below instructions,  I used d:\fpc\linuxlib to store them.
8) go to <fpcbindir>\units\i386-linux\rtl  and copy cprt21.o over cprt0.o
9) enter lazarus dir
10) edit lazarus.pp and add {$linklib dl} and {$linklib gmodule} somewhere in the source.
11) make OS_TARGET=linux all OPT="-gl -Fld:\fpc\linuxlib -Xr/usr/lib -FL/usr/lib/ld-linux.so.2 " 

If some linker error (most specifically linker can't find -l<something>) then

12) manually edit link.res if needed (see below for gtk remarks) and adapt the -l<x> names at the bottom of the files. I had to add -1.2 to all gtk
    libs, to keep them apart from gtk2
13) run ppas.bat to restart the linker

----------- Libraries

These are the libraries I collected for both lazarus and the textmode IDE
(lazarus doesn't need pthread).

I gathered these from the target system, and renamed all from
lib<name>.so.x.y to lib<name>.so.

libgcc.a and a few others are easiest found by doing gcc -v and look for a line like

"Reading specs from /usr/lib/gcc-lib/i486-linux/3.3.5/specs"

then some of the libs are in  /usr/lib/gcc-lib/i486-linux/3.3.5/
Some other good locations are /lib /usr/lib /usr/local/lib /usr/x11R6/lib and /opt/gnome/lib

libpthread.so.0
libdl.so
libc.so
ld-linux.so.2
crtbegin.o
crtbeginS.o
crtbeginT.o
crtend.o
crtendS.o
crtn.o
crti.o
libgcc.a
libX11.so
libXi.so
libglib-1.2.so
libgmodule-1.2.so.0
libgdk_pixbuf.so
libgdk-1.2.so
libgtk-1.2.so
libXext.so
libm.so
libdl.so.2
libgmodule-1.2.so

Note that some directories are duplicate, with a suffix and not. These are required because some other lib has a dependancy on that 
exact name (so the form lib<name>.so.x) we can't symlink on windows, so I simply copy it.

Making mistakes with renaming is not that bad, there will be chances to fix it. Make sure all crt* and a file "libc.so" are available, otherwise
generating link.res will go wrong. (Yes, Peter, that was my fault :-)

In my case compilation for step 11 will go ok, but the linker will complain it can't find libgtk.so and the other libraries marked with -1.2
This is because on the target system, libgtk is gtk 2.0, while we want gtk1.2 for lazarus.

To fix this I manually added -1.2 to the corresponding -l lines in the bottom of the link.res file that was generated by step 11