Added 0readme_pcap-VMS.txt to describe build relationship to simh

Pcap-VMS/0readme_pcap-VMS.txt

@@ -0,0 +1,19 @@
+# The simh source provides a descrip.mms file which builds all of the
+# respective simulators on a VMS host platform.  
+#
+# The VAX and PDP11 simulators can include network support which depends
+# on the PCAP-VMS package provided here.
+#
+# The PCAP-VMS components are presumed to be located in a directory at 
+# the same level as the directory containing the simh source files.  
+# For example, if these exist here:
+#
+#   []descrip.mms
+#   []scp.c
+#   etc.
+#
+# Then the following should exist:
+#   [-.PCAP-VMS]BUILD_ALL.COM
+#   [-.PCAP-VMS.PCAP-VCI]
+#   [-.PCAP-VMS.PCAPVCM]
+#   etc.