Reposting to dev-luatex, seems to be the appropriate place.

On Thu, 06 Sep 2018, Norbert Preining wrote:
> Hi Luigi, hi all,
>
> configuring current TL sources with
>       --with-system-gmp
> I get an error:
> gcc -DHAVE_CONFIG_H -I. -I../../../texk/web2c -I./w2c    -I/usr/include/libpng16  -I/home/norbert/Development/TeX/texlive.git/Build/source/foo/texk -I/home/norbert/Development/TeX/texlive.git/Build/source/texk -I../../../texk/web2c/mplibdir  -Wimplicit -Wreturn-type -g -O2 -MT libmplibcore_a-mpmathbinary.o -MD -MP -MF .deps/libmplibcore_a-mpmathbinary.Tpo -c -o libmplibcore_a-mpmathbinary.o `test -f 'mpmathbinary.c' || echo '../../../texk/web2c/'`mpmathbinary.c
> In file included from ../../../texk/web2c/mplibdir/mpmathbinary.w:28:
> ../../../texk/web2c/mplibdir/mpmathbinary.w:44:10: fatal error: gmp/config.h: No such file or directory
>  #include <gmp/config.h>
>           ^~~~~~~~~~~~~~
> compilation terminated.
>
>
> Debian's libgmp-dev does not ship
>       gmp/config.h
> only
>       gmp.h
>
> Is it now necessary to build with the TL shipped libgmp?

Best

Norbert