Remove $(TIRPCINC) from all Makefile.am files - it no longer exists

Also, restructure some of the dependencies in the lib/tt binaries.  We
will link with libtt (which will include libtirpc as a dependency),
and XTOOLLIB - all the right X11 stuff without needing to add it to
every OS.  Removed several uneeded OS specializations ("if LINUX",
etc) as a result.

cde/programs/dtfile/Makefile.am

@@ -11,7 +11,7 @@ dist_config_DATA = dtfile.config
 
 dist_bin_SCRIPTS = dtfile_error
 
-dtfile_CPPFLAGS = -I./dtcopy $(TIRPCINC) -DSHAPE -D_ILS_MACROS -DSUN_PERF \
+dtfile_CPPFLAGS = -I./dtcopy -DSHAPE -D_ILS_MACROS -DSUN_PERF \
 		-DCDE_INSTALLATION_TOP=\"${prefix}\" \
 		-DCDE_CONFIGURATION_TOP=\"$(CDE_CONFIGURATION_TOP)\" \
 		-DKORNSHELL=\"$(KSH)\" -I/usr/include/freetype2

cde/programs/dtfile/dtcopy/Makefile.am

@@ -2,7 +2,7 @@ MAINTAINERCLEANFILES = Makefile.in
 
 bin_PROGRAMS = dtfile_copy
 
-dtfile_copy_CFLAGS = -DSHAPE $(TIRPCINC)
+dtfile_copy_CFLAGS = -DSHAPE
 
 if SOLARIS
 dtfile_copy_CFLAGS += -xF