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/dtmail/libDtMail/Common/Makefile.am

@@ -3,7 +3,7 @@ MAINTAINERCLEANFILES = Makefile.in
 noinst_LIBRARIES = libCommon.a
 
 libCommon_a_CXXFLAGS = -I../../include -I../../include/utils -I$(srcdir)/lib \
-		       $(TIRPCINC) -DDL_NOT_DYNAMIC -DUSE_SOCKSTREAM
+		       -DDL_NOT_DYNAMIC -DUSE_SOCKSTREAM
 
 if SOLARIS
 libCommon_a_CXXFLAGS += -DMMAP_NORESERVE -DSPRO_V2

cde/programs/dtmail/libDtMail/RFC/Makefile.am

@@ -3,7 +3,7 @@ MAINTAINERCLEANFILES = Makefile.in
 noinst_LIBRARIES = libRFC.a
 
 libRFC_a_CXXFLAGS = -I../Common -I../../include -I../../include/utils \
-		    $(TIRPCINC) -DTTLOCK_OFF
+		    -DTTLOCK_OFF
 
 if SOLARIS
 libRFC_a_CXXFLAGS += -DMMAP_NORESERVE -DSPRO_V2