Merge pull request #1465 from def-/cpp-cstring-len

Include string.h for strlen with cpp backend

compiler/ccgexprs.nim

@@ -1286,6 +1286,7 @@ proc genArrayLen(p: BProc, e: PNode, d: var TLoc, op: TMagic) =
     if op == mHigh: unaryExpr(p, e, d, "($1Len0-1)")
     else: unaryExpr(p, e, d, "$1Len0")
   of tyCString:
+    useStringh(p.module)
     if op == mHigh: unaryExpr(p, e, d, "(strlen($1)-1)")
     else: unaryExpr(p, e, d, "strlen($1)")
   of tyString, tySequence: