[CT-NG:patch 05/19] Force autoreconf for mpfr

In some exotic case the autoreconf step of mpfr is not executed (correctly)
leaving an incorrect version number for libtool in the configure script.

After extracting the sources files, force autoreconf to be executed.

Signed-off-by: Bart vdr. Meulen <bartvdrmeulen@gmail.com>

# Overall toolchain configuration: paths, jobs, etc...

menu "Paths and misc options"

source "config/global/ct-behave.in"

source "config/global/paths.in"

source "config/global/download.in"

source "config/global/extract.in"

source "config/global/build-behave.in"

source "config/global/logging.in"

endmenu