This section shows a radically different way to use Gnulib.
You can extract the ISO C / POSIX substitutes part of gnulib by running the command
gnulib-tool --create-testdir --source-base=lib \
--dir=/tmp/posixlib `posix-modules`
The command ‘posix-modules’ is found in the same directory as
gnulib-tool.
The resulting directory can be built on a particular platform,
independently of the program being ported. Then you can configure and
build any program, by setting CPPFLAGS and LDFLAGS at
configure time accordingly: set CPPFLAGS="-I.../posixlib/lib", plus
any essential type definitions and flags that you find in
.../posixlib/config.h, and set
LDFLAGS=".../posixlib/lib/libgnu.a".
This way of using Gnulib is useful when you don’t want to modify the program’s
source code, or when the program uses a mix between C and C++ sources
(requiring separate builds of the posixlib for the C compiler and
for the C++ compiler).