Use curl for downloading

Author: jeroen

.Rbuildignore

@@ -25,3 +25,4 @@ src\/RCS
 ^revdep$
 ^appveyor.yml$
 ^.github$
+README.md$

DESCRIPTION

@@ -35,4 +35,4 @@ Collate:
     'transaction.R'
 Suggests:
     testthat,
-    RMariaDB
+    curl

tools/winlibs.R

@@ -2,7 +2,7 @@
 # Info and source code: https://downloads.mariadb.org/client-native/
 if(!file.exists("../windows/libmariadbclient-2.3.4/include/mariadb/mysql.h")){
   if(getRversion() < "3.3.0") setInternet2()
-  download.file("https://github.com/rwinlib/libmariadbclient/archive/v2.3.4.zip", "lib.zip", quiet = TRUE)
+  curl::curl_download("https://github.com/rwinlib/libmariadbclient/archive/v2.3.4.zip", "lib.zip")
   dir.create("../windows", showWarnings = FALSE)
   unzip("lib.zip", exdir = "../windows")
   unlink("lib.zip")