Autotools.txt

$ apt install build-essential git perl flex bison gperf \
  automake autoconf libtool pkg-config gettext

$ autoscan
$ mv configure.scan configure.ac

$ cat configure.ac
AC_PREREQ([2.71])
AC_INIT([MyProject], [1.2], [support@email])
AM_INIT_AUTOMAKE([foreign])
AC_CONFIG_MACRO_DIRS([m4])
AM_PROG_AR
LT_INIT
AC_PROG_CC # CXX
AC_CONFIG_HEADERS([config.h])

# put dependency first
AC_CONFIG_FILES([
  Makefile
  foo/Makefile
])

AC_OUTPUT
$

$ cat Makefile.am
ACLOCAL_AMFLAGS = -I m4
bin_PROGRAMS = main
#lib_LTLIBRARIES =
main_SOURCES = main.c
CFLAGS = -std=c99 -g -fPIC # CXXFLAGS
main_CPPFLAGS = # -I./foo
main_LDFLAGS = # -L./foo -lfoo -shared

# rpath for dev
main_LDFLAGS += # -Wl,-rpath,'$$ORIGIN/../foo/.libs'
# rpath for install: make DESTDIR=~/tmp install
main_LDFLAGS += # -Wl,-rpath,'$$ORIGIN/../lib'

# library versioning with soname
main_LDFLAGS += # -release $(PACKAGE_VERSION) -version-info 0:8:0

# put dependency first
SUBDIRS = ./foo
$

$ cat autogen.sh
# usage
# ./autogen
# ./autogen clean

# autogen
if (( $# == 0 )); then
  [[ ! -d m4 ]] && mkdir m4
  autoreconf -i
fi

# clean
if [[ $1 == "clean" ]]; then
  # temporaries by autoreconf -i
  rm -fr aclocal.m4 compile config.* configure \
    configure~ depcomp install-sh m4 missing ar-lib \
    autom4te.cache ltmain.sh

  find . -name "Makefile.in" -exec rm -fr {} \;

  # temporaries by ./configure
  rm -fr libtool stamp-h1
  find . -name ".deps" -type d -exec rm -fr {} \;
  find . -name "Makefile" -exec rm -fr {} \;

  # temporaries by make
  find . \( -name "*.la" -o -name "*.lai" -o -name "*.lo" \
    -o -name "*.d" -o -name "*.o" \) -exec rm -fr {} \;
fi
$

$ autoreconf -i
$ ./configure
$ make
$ ./configure --help


Ref:
Autotools Tutorial, Handout version in PDF
(4 slides per pages without animations, for printing)
https://www.lrde.epita.fr/~adl/dl/autotools-handout-4.pdf