Fix build under LLVM15

Fix many -Wint-conversion errors such as the example below, including
an aso atomics error.

connect.c:87:12: error: incompatible pointer to integer conversion initializing 'LONG' (aka 'int') with an expression of type 'void *' [-Wint-conversion]
   DB_ADDR mdba = NULL;   /* db address of current member record */
           ^      ~~~~

cde/lib/DtHelp/AccessCCDF.c

@@ -59,6 +59,8 @@
 extern int errno;
 #endif
 
+extern char *_DtHelpGetLocale(void);
+
 /*
  * Canvas Engine includes
  */

cde/lib/DtSearch/raima/connect.c

@@ -84,8 +84,8 @@ int dbn  /* Database number */
    char *orec;            /* ptr to current owner record contents in cache */
    char *mrec;            /* ptr to current member record contents in cache */
    char *nrec;            /* ptr to next member record contents in cache */
-   DB_ADDR mdba = NULL;   /* db address of current member record */
-   DB_ADDR ndba = NULL;   /* db address of next member record */
+   DB_ADDR mdba = 0;      /* db address of current member record */
+   DB_ADDR ndba = 0;      /* db address of next member record */
    INT ordering;          /* set order control variable */
    int stat, compare;     /* status code & sort comparison result */
    SET_ENTRY *set_ptr;