Tidy up the autoconf/automake configuration a bit.

- Removed some old cruft.

- Removed some support for older versions of automake which technically was
  correct, but caused the newer automakes to squawk warnings during an
  initial sanity check (which isn't done very intelligently.)

  NOTE: this fix is technically not correct for older version of automake.
  These older version use the variable "INCLUDES" internally and could have
  them already set to an important value.  That is why we were appending
  our values to them.  However, newer versions of automake don't set this
  value themselves so it is an error to append to a non-existant variable.
  We seem to "get away" with overwriting the value on older versions of
  automake, but if you have problems, consider upgrading to at least
  automake-1.5.

configure.in

@@ -128,9 +128,6 @@ dnl enough.  AM_CONDITIONALS are then referenced to conditionally
 dnl build a Makefile.in from a Makefile.am which lets us define custom
 dnl includes, compile alternative source files, etc.
 
-dnl Enable serial support on Unix type systems
-AM_CONDITIONAL(ENABLE_UNIX_SERIAL, true)
-
 dnl X11 might be installed on Mac OS X, don't want to use it if it is.
 if test "x$HOSTTYPE" != "xmacintosh" ; then
     dnl Check for X11 (fancy)
@@ -254,7 +251,9 @@ fi
 if test "x$ac_cv_lib_glut_glutGameModeString" = "xno"; then
     echo
     echo "Your version of glut doesn't support game mode."
-    echo "You need to fetch and install the latest version of glut from:"
+    echo "You need to install the latest version of glut.  If your"
+    echo "distribution doesn't provide a newer version, you can get the source"
+    echo "code from:"
     echo
     echo "    http://reality.sgi.com/opengl/glut3/glut3.html"
     exit 1

simgear/Makefile.am

@@ -1,9 +1,3 @@
-if ENABLE_UNIX_SERIAL
-SERIAL_DIRS = serial
-else
-SERIAL_DIRS =
-endif
-
 if HAVE_THREADS
 SGTHREAD_DIR = threads
 else
@@ -30,7 +24,7 @@ SUBDIRS = \
 	$(METAR_DIRS) \
 	route \
 	screen \
-	$(SERIAL_DIRS) \
+	serial \
 	sky \
 	$(SGTHREAD_DIR) \
 	timing \

simgear/bucket/Makefile.am

@@ -14,8 +14,4 @@ libsgbucket_a_SOURCES = newbucket.cxx
 # 	$(top_builddir)/bucket/libsgbucket.a \
 # 	$(top_builddir)/misc/libsgmisc.a
 
-if OLD_AUTOMAKE
-INCLUDES += -I$(top_srcdir)
-else
 INCLUDES = -I$(top_srcdir)
-endif

simgear/debug/Makefile.am

@@ -8,8 +8,4 @@ include_HEADERS = debug_types.h logstream.hxx
 
 libsgdebug_a_SOURCES = logstream.cxx
 
-if OLD_AUTOMAKE
-INCLUDES += -I$(top_srcdir)
-else
 INCLUDES = -I$(top_srcdir)
-endif

simgear/ephemeris/Makefile.am

@@ -31,8 +31,4 @@ libsgephem_a_SOURCES = \
 	uranus.cxx \
 	venus.cxx
 
-if OLD_AUTOMAKE
-INCLUDES += -I$(top_srcdir)
-else
 INCLUDES = -I$(top_srcdir)
-endif

simgear/interpreter/Makefile.am

@@ -30,8 +30,4 @@ libsginterp_a_SOURCES = \
 	ixlib_js_internals.hh \
 	ixlib_random.hh
 
-if OLD_AUTOMAKE
-INCLUDES += -I$(top_srcdir)
-else
 INCLUDES = -I$(top_srcdir)
-endif

simgear/io/Makefile.am

@@ -20,11 +20,7 @@ libsgio_a_SOURCES = \
 	sg_socket.cxx \
 	sg_socket_udp.cxx 
 
-if OLD_AUTOMAKE
-INCLUDES += -I$(top_srcdir)
-else
 INCLUDES = -I$(top_srcdir)
-endif
 
 if IS_MINGW
 NETWORK_LIB = -lwsock32

simgear/magvar/Makefile.am

@@ -14,8 +14,4 @@ testmagvar_SOURCES = testmagvar.cxx
 
 testmagvar_LDADD = $(top_builddir)/simgear/magvar/libsgmagvar.a
 
-if OLD_AUTOMAKE
-INCLUDES += -I$(top_srcdir)
-else
 INCLUDES = -I$(top_srcdir)
-endif

simgear/math/Makefile.am

@@ -24,8 +24,4 @@ libsgmath_a_SOURCES = \
 	sg_random.c \
 	vector.cxx
 
-if OLD_AUTOMAKE
-INCLUDES += -I$(top_srcdir)
-else
 INCLUDES = -I$(top_srcdir)
-endif

simgear/metar/Makefile.am

@@ -11,8 +11,4 @@ libsgmetar_a_SOURCES = \
 	MetarStation.cpp \
 	Prtdmetr.cpp Stspack2.cpp Stspack3.cpp
 
-if OLD_AUTOMAKE
-INCLUDES += -I$(top_srcdir)
-else
 INCLUDES = -I$(top_srcdir)
-endif

simgear/misc/Makefile.am

@@ -30,8 +30,4 @@ noinst_PROGRAMS = props_test
 props_test_SOURCES = props_test.cxx
 props_test_LDADD = libsgmisc.a ../xml/libsgxml.a ../debug/libsgdebug.a
 
-if OLD_AUTOMAKE
-INCLUDES += -I$(top_srcdir)
-else
 INCLUDES = -I$(top_srcdir)
-endif

simgear/route/Makefile.am

@@ -8,11 +8,7 @@ libsgroute_a_SOURCES = \
 	route.cxx \
 	waypoint.cxx
 
-if OLD_AUTOMAKE
-INCLUDES += -I$(top_srcdir)
-else
 INCLUDES = -I$(top_srcdir)
-endif
 
 noinst_PROGRAMS = waytest routetest
 

simgear/screen/Makefile.am

@@ -19,8 +19,4 @@ libsgscreen_a_SOURCES = \
         tr.cxx \
 	win32-printer.h
 
-if OLD_AUTOMAKE
-INCLUDES += -I$(top_srcdir)
-else
 INCLUDES = -I$(top_srcdir)
-endif

simgear/serial/Makefile.am

@@ -14,8 +14,4 @@ testserial_LDADD = \
 	$(top_builddir)/simgear/serial/libsgserial.a \
 	$(top_builddir)/simgear/debug/libsgdebug.a
 
-if OLD_AUTOMAKE
-INCLUDES += -I$(top_srcdir)
-else
 INCLUDES = -I$(top_srcdir)
-endif

simgear/sky/Makefile.am

@@ -20,8 +20,4 @@ libsgsky_a_SOURCES = \
 	sphere.cxx \
 	stars.cxx
 
-if OLD_AUTOMAKE
-INCLUDES += -I$(top_srcdir)
-else
 INCLUDES = -I$(top_srcdir)
-endif

simgear/threads/Makefile.am

@@ -10,8 +10,4 @@ include_HEADERS = \
 libsgthreads_a_SOURCES = \
 	SGThread.cxx
 
-if OLD_AUTOMAKE
-INCLUDES += -I$(top_srcdir)
-else
 INCLUDES = -I$(top_srcdir)
-endif

simgear/timing/Makefile.am

@@ -16,8 +16,4 @@ libsgtiming_a_SOURCES = \
 	timestamp.cxx \
 	timezone.cxx
 
-if OLD_AUTOMAKE
-INCLUDES += -I$(top_srcdir)
-else
 INCLUDES = -I$(top_srcdir)
-endif

simgear/xgl/Makefile.am

@@ -6,8 +6,4 @@ include_HEADERS = xgl.h
 
 libsgxgl_a_SOURCES = xgl.c xglUtils.c
 
-if OLD_AUTOMAKE
-INCLUDES += -I$(top_srcdir)
-else
 INCLUDES = -I$(top_srcdir)
-endif

simgear/xml/Makefile.am

@@ -18,8 +18,4 @@ libsgxml_a_SOURCES = \
 	xmltok.h xmltok.c \
 	xmltok_impl.h
 
-if OLD_AUTOMAKE
-INCLUDES += -I$(top_srcdir)
-else
 INCLUDES = -I$(top_srcdir)
-endif