Fix dbConstLink to handle a long-string array properly

Added a new parser dbLSConvertJSON for long-string arrays.
New test checks that only the first string element is used.

src/std/rec/test/linkInitTest.c

@@ -53,6 +53,8 @@ static void testLongStringInit()
         testdbGetFieldEqual("longstr3.VAL", DBR_STRING, "!--------------------------------------");
     }
 
+    testdbGetFieldEqual("longstr4.VAL", DBR_STRING, "One");
+
     testIocShutdownOk();
 
     testdbCleanup();
@@ -149,7 +151,7 @@ static void testPrintfInit()
 
 MAIN(linkInitTest)
 {
-    testPlan(30);
+    testPlan(31);
     testLongStringInit();
     testCalcInit();
     testPrintfInit();

src/std/rec/test/linkInitTest.db

@@ -1,4 +1,3 @@
-
 record(lsi, "longstr1") {
   field(SIZV, "100")
   field(INP, ["!----------------------------------------------!"])
@@ -14,6 +13,10 @@ record(lsi, "longstr3") {
   field(INP, {const: "!----------------------------------------------!"})
 }
 
+record(stringin, "longstr4") {
+  field(INP, ["One","Two","Three","Four"])
+}
+
 record(ai, "emptylink" ) {
   field(INP, {calc: {expr:"0"}})
 }