doc: Add reportlab install info

[abmusse]

pip installing reportlab with python3.9 fails building _renderPM extension.

    In file included from /usr/include/sys/thread.h:41:0,
                     from /usr/include/sys/ptrace.h:28,
                     from /usr/include/sys/proc.h:42,
                     from /usr/include/sys/pri.h:43,
                     from /usr/include/sys/sched.h:38,
                     from /usr/include/sched.h:51,
                     from /usr/include/pthread.h:67,
                     from /QOpenSys/pkgs/include/python3.9/pythread.h:128,
                     from /QOpenSys/pkgs/include/python3.9/Python.h:131,
                     from src/rl_addons/renderPM/_renderPM.c:1:
    src/rl_addons/renderPM/libart_lgpl/art_pixbuf.h:38:41: error: expected ';', ',' or ')' before '.' token
     typedef void (*ArtDestroyNotify) (void *func_data, void *data);
                                             ^
    In file included from src/rl_addons/renderPM/libart_lgpl/libart.h:11:0,
                     from src/rl_addons/renderPM/_renderPM.c:11:
    src/rl_addons/renderPM/libart_lgpl/art_pixbuf.h:63:3: error: unknown type name 'ArtDestroyNotify'
       ArtDestroyNotify destroy;
       ^~~~~~~~~~~~~~~~
    src/rl_addons/renderPM/libart_lgpl/art_pixbuf.h:83:26: error: unknown type name 'ArtDestroyNotify'
            void *dfunc_data, ArtDestroyNotify dfunc);
                              ^~~~~~~~~~~~~~~~
    src/rl_addons/renderPM/libart_lgpl/art_pixbuf.h:87:27: error: unknown type name 'ArtDestroyNotify'
             void *dfunc_data, ArtDestroyNotify dfunc);

Workaround to resolve the build failure is to define _LINUX_SOURCE_COMPAT.

[kadler]

I think your changes have good info, but most users don't need to know or care about that level of detail. Instead something like this would be more useful to them:

When installing reportlab, you may encounter a compile error such as

   src/rl_addons/renderPM/libart_lgpl/art_pixbuf.h:38:41: error: expected ';', ',' or ')' before '.' token
    typedef void (*ArtDestroyNotify) (void *func_data, void *data);
                                            ^

This is due to a conflict in the reportlab source code and the AIX header files. As a workaround, you can define _LINUX_SOURCE_COMPAT to prevent the conflicting definition:

CFLAGS=-D_LINUX_SOURCE_COMPAT pip3 install reportlab`

[abmusse]

I think your changes have good info, but most users don't need to know or care about that level of detail. Instead something like this would be more useful to them:

When installing reportlab, you may encounter a compile error such as

   src/rl_addons/renderPM/libart_lgpl/art_pixbuf.h:38:41: error: expected ';', ',' or ')' before '.' token
    typedef void (*ArtDestroyNotify) (void *func_data, void *data);
                                            ^

This is due to a conflict in the reportlab source code and the AIX header files. As a workaround, you can define _LINUX_SOURCE_COMPAT to prevent the conflicting definition:

CFLAGS=-D_LINUX_SOURCE_COMPAT pip3 install reportlab`

Thanks for cutting it down. I will make the suggested change!

[vint7k]

It appears to me that I am facing the same issue while installing the reportlab package on IBM i V7R3.

could you please suggest CFLAGS=-D_LINUX_SOURCE_COMPAT pip3 install reportlab` if this worked in resolving the issue during the wheel build of reportlab.

We are using python3.9 and pillow version 8.3.1 default from IBM i repo.