title: R CMD check NOTEs GitHub URL as (possibly) invalid
body: <p>I am attempting to release an R package, and like many packages I have the <a href="https://github.com/paulhibbing/TwoRegression" rel="nofollow noreferrer">GitHub page</a> listed in DESCRIPTION and CITATION. The issues page is also listed in DESCRIPTION.</p>
  
  <p>The package passes <code>devtools::build_win()</code> and <a href="https://travis-ci.org/paulhibbing/TwoRegression" rel="nofollow noreferrer">builds on Travis CI</a>. The only NOTE I get in either of those cases is the one about it being the package's first submission.</p>
  
  <p>But when I run <code>devtools::release()</code>, the NOTE includes the following, which is repeated for each instance in which I give a GitHub URL:</p>
  
  <blockquote>
    <p>Found the following (possibly) invalid URLs:<br>
    URL:
    <a href="https://github.com/paulhibbing/TwoRegression" rel="nofollow noreferrer">https://github.com/paulhibbing/TwoRegression</a><br>
        From: DESCRIPTION<br>
        Status: Error<br>
        Message: libcurl error code 35<br>
          error:1407742E:SSL routines:SSL23_GET_SERVER_HELLO:tlsv1 alert protocol version</p>
  </blockquote>
  
  <p>Here is my session info:</p>
  
  <blockquote>
    <p>R version 3.2.4 Revised (2016-03-16 r70336) Platform:
    i386-w64-mingw32/i386 (32-bit) Running under: Windows >= 8 x64 (build
    9200)</p>
    
    <p>locale: <a href="https://github.com/paulhibbing/TwoRegression" rel="nofollow noreferrer">1</a> LC_COLLATE=English_United States.1252 
    LC_CTYPE=English_United States.1252    [3] LC_MONETARY=English_United
    States.1252 LC_NUMERIC=C                           [5]
    LC_TIME=English_United States.1252    </p>
    
    <p>attached base packages: <a href="https://github.com/paulhibbing/TwoRegression" rel="nofollow noreferrer">1</a> stats     graphics  grDevices utils<br>
    datasets  methods   base     </p>
    
    <p>other attached packages: <a href="https://github.com/paulhibbing/TwoRegression" rel="nofollow noreferrer">1</a> TwoRegression_0.1</p>
    
    <p>loaded via a namespace (and not attached):  <a href="https://github.com/paulhibbing/TwoRegression" rel="nofollow noreferrer">1</a> Rcpp_0.12.10<br>
    rstudioapi_0.7    xml2_1.1.1        magrittr_1.5      roxygen2_6.0.1<br>
    [6] devtools_1.12.0   MASS_7.3-45       R6_2.2.2<br>
    stringr_1.2.0     dplyr_0.5.0       [11] tools_3.2.4<br>
    data.table_1.10.5 DBI_0.7           withr_2.0.0       commonmark_1.2<br>
    [16] rprojroot_1.3-2   digest_0.6.12     assertthat_0.2.0 
    tibble_1.3.0      crayon_1.3.4      [21] tuneR_1.3.2<br>
    testthat_1.0.2    curl_2.5          signal_0.7-6      seewave_2.0.5<br>
    [26] memoise_1.1.0     stringi_1.1.5     backports_1.1.1   desc_1.1.1</p>
  </blockquote>
  
  <p>I have tried updating <code>curl</code> from source, but it fails with:</p>
  
  <blockquote>
    <p>c:/rtools/gcc-4.6.3/bin/../lib/gcc/i686-w64-mingw32/4.6.3/../../../../i686-w64-mingw32/bin/ld.exe:<br>
    cannot find -lz collect2: ld returned 1 exit status no DLL was created<br>
    ERROR: compilation failed for package 'curl'<br>
    * removing 'C:/Users/Paul/Documents/R/win-library/3.2/curl'<br>
    * restoring previous 'C:/Users/Paul/Documents/R/win-library/3.2/curl' Warning in install.packages :   running command<br>
    '"C:/PROGRA~1/R/R-32~1.4RE/bin/i386/R" CMD INSTALL -l<br>
    "C:\Users\Paul\Documents\R\win-library\3.2"<br>
    C:\Users\Paul\AppData\Local\Temp\RtmpAflnM7/downloaded_packages/curl_3.1.tar.gz'<br>
    had status 1 Warning in install.packages :   installation of package<br>
    ‘curl’ had non-zero exit status</p>
  </blockquote>
  
  <p>I have curl 7.58.0 and OpenSSL 1.1.0f installed on my system, and running <code>curl -I -L https://github.com/paulhibbing/TwoRegression</code> gives:</p>
  
  <blockquote>
    <p>HTTP/1.1<br>
    200 OK<br>
    Server: GitHub.com<br>
    Date: Sun, 11 Mar 2018 22:07:34 GMT<br>
    Content-Type: text/html; charset=utf-8 Status: 200 OK Cache-Control:<br>
    no-cache Vary: X-PJAX X-UA-Compatible: IE=Edge,chrome=1 Set-Cookie:<br>
    logged_in=no; domain=.github.com; path=/; expires=Thu, 11 Mar 2038<br>
    22:07:34 -0000; secure; HttpOnly Set-Cookie:  </p>
    
    <p>_gh_sess=eyJzZXNzaW9uX2lkIjoiODc0MWFkMDU3Y2FhMTU0MDdlMTZkZDkyZmQzNGEyMmEiLCJsYXN0X3JlYWRfZnJvbV9yZXBsaWNhcyI6MTUyMDgwNjA1NDE1OSwic3B5X3JlcG8iOiJwYXVsaGliYmluZy9Ud29SZWdyZXNzaW9uIiwic3B5X3JlcG9fYXQiOjE1MjA4MDYwNTQsIl9jc3JmX3Rva2VuIjoiS3N2UWhwaWl4c1Q0aTFNellwZEF3bUhZbElhdDlvenVsdFQxSWo1VmtSWT0iLCJmbGFzaCI6eyJkaXNjYXJkIjpbImFuYWx5dGljc19sb2NhdGlvbiJdLCJmbGFzaGVzIjp7ImFuYWx5dGljc19sb2NhdGlvbiI6Ii88dXNlci1uYW1lPi88cmVwby1uYW1lPiJ9fX0%3D--60ed8470ecfccac7fb7187791e4f09f737c1db04;<br>
    path=/; secure; HttpOnly X-Request-Id:<br>
    2e7029a9039c25f5ff66f76f9c6d6f59 X-Runtime: 0.214595 Expect-CT:<br>
    max-age=2592000,<br>
    report-uri="https://api.github.com/_private/browser/errors"<br>
    Content-Security-Policy: default-src 'none'; base-uri 'self';<br>
    block-all-mixed-content; child-src render.githubusercontent.com;<br>
    connect-src 'self' uploads.github.com status.github.com<br>
    collector.githubapp.com api.github.com www.google-analytics.com<br>
    github-cloud.s3.amazonaws.com<br>
    github-production-repository-file-5c1aeb.s3.amazonaws.com<br>
    github-production-upload-manifest-file-7fdce7.s3.amazonaws.com<br>
    github-production-user-asset-6210df.s3.amazonaws.com<br>
    wss://live.github.com; font-src assets-cdn.github.com; form-action<br>
    'self' github.com gist.github.com; frame-ancestors 'none'; img-src<br>
    'self' data: assets-cdn.github.com identicons.github.com<br>
    collector.githubapp.com github-cloud.s3.amazonaws.com<br>
    *.githubusercontent.com; manifest-src 'self'; media-src 'none'; script-src assets-cdn.github.com; style-src 'unsafe-inline'<br>
    assets-cdn.github.com; worker-src 'self' Strict-Transport-Security:<br>
    max-age=31536000; includeSubdomains; preload X-Content-Type-Options:<br>
    nosniff X-Frame-Options: deny X-XSS-Protection: 1; mode=block<br>
    X-Runtime-rack: 0.222647 X-GitHub-Request-Id:<br>
    D287:1BDE1:342EA0F:5B4AB8A:5AA5A8A5  </p>
  </blockquote>
  
  <p>So my questions are:<br>
  1. Why do I get the NOTE about invalid URLs?<br>
  2. If it is an issue with <code>curl_2.5</code>, why am I unable to install <code>curl_3.1</code> from source?</p>