Simplification to the StrAccum object and the sqlite3StrAccumAppend()
method that also results in slightly better performance.

FossilOrigin-Name: 700dbbea8647e0fdaee6d0aba3d3dd8ebfbac04a
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index bde4008..025bb46 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -2425,10 +2425,11 @@
   int  nChar;          /* Length of the string so far */
   int  nAlloc;         /* Amount of space allocated in zText */
   int  mxAlloc;        /* Maximum allowed string length */
-  u8   mallocFailed;   /* Becomes true if any memory allocation fails */
   u8   useMalloc;      /* 0: none,  1: sqlite3DbMalloc,  2: sqlite3_malloc */
-  u8   tooBig;         /* Becomes true if string size exceeds limits */
+  u8   accError;       /* STRACCUM_NOMEM or STRACCUM_TOOBIG */
 };
+#define STRACCUM_NOMEM   1
+#define STRACCUM_TOOBIG  2
 
 /*
 ** A pointer to this structure is used to communicate information