attempt to disable pvalink for Base <3.16

Seems to work, but prints messages showing that there
is still some problem, probably with a ".dep".
Of course these are silent rules, so I have no idea
which one!

> dbdExpand.pl: No input files for ../O.Common/qsrv.dbd

pdbApp/Makefile

@@ -34,19 +34,24 @@ qsrv_SRCS += pvif.cpp
 qsrv_SRCS += qsrv.cpp
 qsrv_SRCS += pdb.cpp
 qsrv_SRCS += pdbsingle.cpp
-qsrv_SRCS += dbf_copy.cpp
-qsrv_SRCS += pvalink.cpp
-qsrv_SRCS += pvalink_lset.cpp
-qsrv_SRCS += pvalink_jlif.cpp
-qsrv_SRCS += pvalink_link.cpp
-qsrv_SRCS += pvalink_channel.cpp
-qsrv_SRCS += tpool.cpp
 qsrv_SRCS += demo.cpp
 qsrv_SRCS += imagedemo.c
 
 ifdef BASE_3_16
 qsrv_SRCS += pdbgroup.cpp
 qsrv_SRCS += configparse.cpp
+
+qsrv_SRCS += dbf_copy.cpp
+qsrv_SRCS += tpool.cpp
+
+qsrv_SRCS += pvalink.cpp
+qsrv_SRCS += pvalink_lset.cpp
+qsrv_SRCS += pvalink_jlif.cpp
+qsrv_SRCS += pvalink_link.cpp
+qsrv_SRCS += pvalink_channel.cpp
+else
+
+qsrv_SRCS += pvalink_null.cpp
 endif
 
 qsrv_LIBS += pvAccess pvData
@@ -86,3 +91,13 @@ include $(TOP)/configure/RULES
 
 qsrv$(DEP): ../O.Common/pv/qsrvVersionNum.h
 pvalink$(DEP): ../O.Common/pv/qsrvVersionNum.h
+
+ifdef BASE_3_16
+../O.Common/qsrv.dbd: ../qsrv-new.dbd
+	$(CP) $< $@
+else
+../O.Common/qsrv.dbd: ../qsrv-old.dbd
+	$(CP) $< $@
+endif
+
+../O.Common/softIocPVA.dbd: ../O.Common/qsrv.dbd

pdbApp/pvalink_null.cpp

@@ -0,0 +1,16 @@
+
+#include <epicsExport.h>
+
+static void installPVAAddLinkHook() {}
+
+struct jlif {} lsetPVA;
+
+extern "C" {
+int pvaLinkDebug;
+int pvaLinkNWorkers;
+
+    epicsExportRegistrar(installPVAAddLinkHook);
+    epicsExportAddress(jlif, lsetPVA);
+    epicsExportAddress(int, pvaLinkDebug);
+    epicsExportAddress(int, pvaLinkNWorkers);
+}

pdbApp/qsrv-old.dbd

@@ -0,0 +1,19 @@
+# Changes to this file may require incrementing
+# the ABI version in CONFIG_QSRV_VERSION
+
+registrar(QSRVRegistrar)
+registrar(installPVAAddLinkHook)
+
+# from demo.cpp
+device(waveform, CONSTANT, devWfPDBDemo, "QSRV Demo")
+# from imagedemo.c
+function(QSRV_image_demo)
+# from pvif.cpp
+# Disable mapping of display.format
+variable(qsrvDisableFormat, int)
+# from pdb.cpp
+# Extra debug info when parsing group definitions
+variable(PDBProviderDebug, int)
+# Number of worker threads for handling monitor updates.
+# Default: 1
+variable(pvaLinkNWorkers, int)

testApp/Makefile

@@ -47,13 +47,13 @@ TESTS += testpdb
 PROD_HOST += check_consist
 check_consist_SRCS += check_consist.cpp
 
+ifdef BASE_3_16
 TESTPROD_HOST += testpvalink
 testpvalink_SRCS += testpvalink.cpp
 testpvalink_SRCS += pvaLinkTestIoc_registerRecordDeviceDriver.cpp
 testpvalink_LIBS += qsrv
 TESTS += testpvalink
 
-ifdef BASE_3_16
 TESTPROD_HOST += testgroupconfig
 testgroupconfig_SRCS += testgroupconfig
 testgroupconfig_LIBS += qsrv pvAccess pvData