added Makefile.inc which can be included from other makefiles to reduce maintaining.

# ./lib/Makefile.inc

CSOURCES = file.c timeval.c base64.c hostip.c progress.c formdata.c	\

  cookie.c http.c sendf.c ftp.c url.c dict.c if2ip.c speedcheck.c	\

  getdate.c ldap.c ssluse.c version.c getenv.c escape.c mprintf.c	\

  telnet.c netrc.c getinfo.c transfer.c strequal.c easy.c security.c	\

  krb4.c memdebug.c http_chunks.c strtok.c connect.c llist.c hash.c	\

  multi.c content_encoding.c share.c http_digest.c md5.c		\

  http_negotiate.c http_ntlm.c inet_pton.c strtoofft.c strerror.c	\

  hostares.c hostasyn.c hostip4.c hostip6.c hostsyn.c hostthre.c	\

  inet_ntop.c

HHEADERS = arpa_telnet.h netrc.h file.h timeval.h base64.h hostip.h	\

  progress.h formdata.h cookie.h http.h sendf.h ftp.h url.h dict.h	\

  if2ip.h speedcheck.h urldata.h getdate.h ldap.h ssluse.h escape.h	\

  telnet.h getinfo.h strequal.h security.h krb4.h memdebug.h		\

  inet_ntoa_r.h http_chunks.h strtok.h connect.h llist.h hash.h		\

  content_encoding.h share.h md5.h http_digest.h http_negotiate.h	\

  http_ntlm.h ca-bundle.h inet_pton.h strtoofft.h strerror.h		\

  inet_ntop.h curlx.h memory.h setup.h transfer.h

# ./src/Makefile.inc

# libcurl has sources that provide functions named curlx_* that aren't part of

# the official API, but we re-use the code here to avoid duplication.

CURLX_ONES =  $(top_srcdir)/lib/strtoofft.c $(top_srcdir)/lib/timeval.c

CURL_SOURCES = main.c hugehelp.c urlglob.c writeout.c writeenv.c \

	getpass.c homedir.c

CURL_HEADERS = hugehelp.h setup.h config-win32.h config-mac.h \

	config-vms.h config-riscos.h urlglob.h version.h \

	writeout.h writeenv.h getpass.h homedir.h

curl_SOURCES = $(CURL_SOURCES) $(CURLX_ONES) $(CURL_HEADERS)