[maemo-developers] Thumb and VFP support in Maemo-Builder

[From: Glen Ditchfield]

Andrew Zabolotny wrote:
> As far as I understand, enabling these DEB_BUILD_OPTION's in the
> builder should not affect older packages that do not have support for
> thumb and/or vfp. So, maybe it would make sense to enable these
> options in maemo builder?

I believe they are enabled.  Take a look at
https://garage.maemo.org/builder/chinook/fribidi_0.10.9-1maemo2/armel.build.log.OK.txt
https://garage.maemo.org/builder/diablo/fribidi_0.10.9-1maemo2/armel.build.log.OK.txt

Near the top, they have lines saying
    DEB_BUILD_OPTIONS="maemo-launcher,thumb,vfp,parallel=4"

I have a question about how to support "thumb".  The GCC 3.4.6 manual,
http://gcc.gnu.org/onlinedocs/gcc-3.4.6/gcc/ARM-Options.html#ARM-Options,
says the compiler supports two thumb flags:

  -mthumb-interwork
Generate code which supports calling between the ARM and Thumb instruction
sets. Without this option the two instruction sets cannot be reliably used
inside one program. The default is -mno-thumb-interwork, since slightly
larger code is generated when -mthumb-interwork is specified. 

  -mthumb
Generate code for the 16-bit Thumb instruction set. The default is to use
the 32-bit ARM instruction set. 

The example in the policy document v0.23 only uses -mthumb.  Should we
use -mthumb-interwork?  Or should we use both?