__ieee754_lgamma_r reentrency with nano.specs

[Damien Nicolet]

>
> > I'm using newlib on an stm32 from debian sid libnewlib-arm-none-eabi
> > package, but I also have the problem with ARM provided toolchain
> > (gcc-arm-none-eabi-8-2019-q3-update).
>
> Are you using the libnewlib-nano-arm-none-eabi package, or the
> libnewlib-arm-none-eabi package?


I'm using the libnewlib-arm-none-eabi. Nothing fancy, just
"--specs=nano.specs" in CFGLAG and LDFLAGS, and "-lm" in LDFLAGS.


> I package the smaller one
> (libnewlib-nano-arm-none-eabi), and that is built from a different tree
> with many changes, which would make cross-linking fail. Given the
> potential for confusion, the smaller one has been renamed 'picolibc'.
>

I tried libnewlib-nano-arm-none-eabi debian package. The version of
picolibc in it is a little bit old and missing some functionalities (sbrk
and _ios) that were added in the current git version. The git version is
very easy to use (thanks to picolibc.specs), but I have some trouble cross
compiling a dependency with it for now.


> Remember to get your include paths and library paths set correctly so
> that you get headers and libraries that match, and that match the
> compiler arguments you're using to build your code.
>

I think I'm doing it correctly. Maybe I am missing something, but I don't
see any specific version of libm using the small struct _reent for signgam
in __ieee754_lgamma_r when used with nano.specs. I will try to put together
a small example of the problem.

Damien