Add mechanism to skip modules for selected architectures

configure/RULES_BUILD

@@ -83,6 +83,23 @@ endif
 
 -include $(CONFIG)/RULES.Db
 
+#---------------------------------------------------------------
+# Do not build anything if current path matches SKIP_BUILD
+
+ifneq (,$(strip $(SKIP_BUILDS)))
+CURRENT_MODULE=$(subst $(realpath $(TOP)/..)/,,$(subst $(realpath $(dir $(lastword $(MAKEFILE_LIST)))..)/,,$(realpath ..)))
+ifneq ($(filter $(SKIP_BUILDS) $(addsuffix /%,$(SKIP_BUILDS)),$(CURRENT_MODULE)),)
+$(info Skipping $(CURRENT_MODULE) for $(T_A))
+PROD=
+TESTPROD=
+LIBRARY=
+TESTLIBRARY=
+LOADABLE_LIBRARY=
+TESTS=
+SRC_FILES=
+endif
+endif
+
 #---------------------------------------------------------------
 # Include defines and rules for prod, library and test* targets
 

documentation/RELEASE_NOTES.html

@@ -18,6 +18,15 @@
 
 -->
 
+<h3>Skipping build of modules</h3>
+
+<p>Any module can be skipped during the build for a given architecture by setting
+the variable <tt>SKIP_BUILDS</tt> to a list of patterns matching the
+module directories to skip. For example to skip building any pvAccess related
+modules set <code>SKIP_BUILDS=pv%&nbsp;normativeTypes</code> in the
+CONFIG.Common.&lt;arch&gt; file for that architecture.
+</p>
+
 <h3>Git Branches Recombined</h3>
 
 <p>The four separate Git branches <tt>core/master</tt>, <tt>libcom/master</tt>,
@@ -28,7 +37,6 @@ more than one of these modules. The layout of the source files has not changed
 at all however, so the source code for libcom, ca and the database are still
 found separately under the module subdirectory.</p>
 
-
 <h1 align="center">EPICS Release 7.0.1.1</h1>
 
 <h3>Changed SIML failure behavior</h3>