Gnulib config.h missing error

Question

I'm trying to port libisofs to Windows. My environment is MSYS2 with mingw-w64-i686 toolchain installed.

I've used gnulib for missing headers with gnulib-tool --import command:

$ ../gnulib/gnulib-tool --import fnmatch

I've done all steps in instruction:

Don't forget to
  - add "lib/Makefile" to AC_CONFIG_FILES in ./configure.ac,
  - mention "lib" in SUBDIRS in Makefile.am,
  - mention "-I m4" in ACLOCAL_AMFLAGS in Makefile.am,
  - mention "m4/gnulib-cache.m4" in EXTRA_DIST in Makefile.am,
  - invoke gl_EARLY in ./configure.ac, right after AC_PROG_CC,
  - invoke gl_INIT in ./configure.ac.

Altough, there was no AC_PROG_CC in configure.ac, so I've added gl_EARLY after AM_PROG_CC_C_O And there was no SUBDIRS variable in Makefile.am so I've added it manually at the bottom, as so:

SUBDIRS = lib

All configurations I've made as so:

autoreconf -i
automake --add-missing
autoconf
./configure

After running make I recieve error:

hard-locale.c:19:10: fatal error: config.h: No such file or directory
 #include <config.h>

As I understand that file must be created by ./configure, but I don't understand why compiler doesn't find it.

configure.ac: https://pastebin.com/JbWRqjEv
Makefile.am: https://pastebin.com/V6ZBq8Vd
All outputs: https://pastebin.com/WFu5aJU7

Answer 1

Gnulib assumes that your configure.ac file contains

AC_CONFIG_HEADERS([config.h])

Without it, every compiler command invocation is more than 1000 characters long, due to the many -D options; this is not practical for development.