Convert build process to use autotools (autoconf, automake, etc.)

This commit converts the build process from a hand-written Makefile
that works on Linux, FreeBSD, and macOS, to an automatically generated
Makefile managed by the autotools toolset.

This incldues:

* Add the compile, config.guess, config.sub, depcomp, install-sh, and
  missing helper scripts that autotools requires to be shipped with
  the package in order for configure to work.
* Rename Makefile to Makefile.am and restructure it for compatibility
  with autotools and specifically with the stuff in our configure
  script.
* Create the configure.ac source file which is turned into the
  configure script.
* Rename Doxyfile to Doxyfile.in so that the source directories can be
  substituted into it at configure time.
* Tweak .gitignore to ignore temporary and output files related to
  autotools.
* Generate Makefile.in, aclocal.m4, and configure using `autoreconf`
  and include them as checked-in source files.

While I can't fully document how autotools works here the basic
workflow is that when you need to make changes to the build, you
update Makefile.am and/or configure.ac as needed, run `autoreconf`,
and commit the changes you made as well as any resulting changes to
Makefile.in, aclocal.m4, and configure. Makefile should _not_ be
committed into the source tree; it should always be generated using
configure on the system where the build is being run.

.gitignore

@@ -14,5 +14,17 @@ doc/html
 *.c~
 *.h~
 
+# autotools
+autom4te.cache
+
 #Others
 mnt
+
+# Generated files
+Doxyfile
+Makefile
+config.log
+config.status
+doc
+src/.deps
+src/.dirstamp

Doxyfile → Doxyfile.in

@@ -790,8 +790,7 @@ WARN_LOGFILE           =
 # spaces. See also FILE_PATTERNS and EXTENSION_MAPPING
 # Note: If this tag is empty the current directory is searched.
 
-INPUT                  = . \
-                         src
+INPUT                  = @srcdir@ @srcdir@/src
 
 # This tag can be used to specify the character encoding of the source files
 # that doxygen parses. Internally doxygen uses the UTF-8 encoding. Doxygen uses

Makefile.am

@@ -0,0 +1,36 @@
+bin_PROGRAMS = httpdirfs
+httpdirfs_SOURCES = src/main.c src/network.c src/fuse_local.c src/link.c \
+	src/cache.c src/util.c src/sonic.c src/log.c src/config.c src/memcache.c
+# This has $(fuse_LIBS) in it because there's a bug in the fuse pkgconf:
+# it should add -pthread to CFLAGS but doesn't.
+# $(NUCLA) is explained in configure.ac.
+CFLAGS = -g -O2  -Wall -Wextra -Wshadow $(NUCLA) \
+	-rdynamic -D_GNU_SOURCE -DVERSION=\"$(VERSION)\"\
+        $(pkgconf_CFLAGS) $(fuse_CFLAGS) $(fuse_LIBS)
+LIBS += $(pkgconf_LIBS) $(fuse_LIBS)
+man_MANS = doc/man/httpdirfs.1
+CLEANFILES = doc/man/*
+DISTCLEANFILES = doc/html/*
+
+# %.o: $(srcdir)/src/%.c
+# 	$(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) -c -o $@ $<
+
+# httpdirfs: $(COBJS)
+# 	$(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) -o $@ $^ $(LIBS)
+
+man: doc/man/httpdirfs.1
+
+doc/man/httpdirfs.1: httpdirfs
+	mkdir -p doc/man
+	rm -f doc/man/httpdirfs.1.tmp
+	help2man --name "mount HTTP directory as a virtual filesystem" \
+		--no-discard-stderr ./httpdirfs > doc/man/httpdirfs.1.tmp
+	mv doc/man/httpdirfs.1.tmp doc/man/httpdirfs.1
+
+doc:
+	doxygen Doxyfile
+
+format:
+	astyle --style=kr --align-pointer=name --max-code-length=80 src/*.c src/*.h
+
+.PHONY: man doc format