<p dir="auto">Seems like getgrouplist is slightly different on darwin.</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="$ man getgrouplist

GETGROUPLIST(3)          BSD Library Functions Manual          GETGROUPLIST(3)

NAME
     getgrouplist -- calculate partial group access list

LIBRARY
     Standard system libraries.

SYNOPSIS
     #include &lt;unistd.h&gt;

     int
     getgrouplist(const char *name, int basegid, int *groups, int *ngroups);"><pre class="notranslate"><code class="notranslate">$ man getgrouplist

GETGROUPLIST(3)          BSD Library Functions Manual          GETGROUPLIST(3)

NAME
     getgrouplist -- calculate partial group access list

LIBRARY
     Standard system libraries.

SYNOPSIS
     #include &lt;unistd.h&gt;

     int
     getgrouplist(const char *name, int basegid, int *groups, int *ngroups);
</code></pre></div>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="# os/user
os/user/lookup_unix.go:43:35: warning: passing 'gid_t *' (aka 'unsigned int *') to parameter of type 'int *' converts between pointers to integer types with different sign [-Wpointer-sign]
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.11.sdk/usr/include/unistd.h:653:43: note: passing argument to parameter here"><pre class="notranslate"><code class="notranslate"># os/user
os/user/lookup_unix.go:43:35: warning: passing 'gid_t *' (aka 'unsigned int *') to parameter of type 'int *' converts between pointers to integer types with different sign [-Wpointer-sign]
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.11.sdk/usr/include/unistd.h:653:43: note: passing argument to parameter here
</code></pre></div>
<p dir="auto">Please answer these questions before submitting your issue. Thanks!</p>
<ol dir="auto">
<li>What version of Go are you using (<code class="notranslate">go version</code>)?</li>
</ol>
<p dir="auto">go version devel +8969ab8 Mon Mar 7 22:41:22 2016 +0000 darwin/amd64</p>
<ol dir="auto">
<li>What operating system and processor architecture are you using (<code class="notranslate">go env</code>)?</li>
</ol>
<p dir="auto">mac osx 10.11.3</p>
<p dir="auto">gcc --version<br>
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.11.sdk/usr/include/c++/4.2.1<br>
Apple LLVM version 7.0.0 (clang-700.0.72)<br>
Target: x86_64-apple-darwin15.3.0<br>
Thread model: posix</p>
<ol dir="auto">
<li>What did you do?</li>
</ol>
<p dir="auto">./make.bash. I am now seeing</p>
<p dir="auto">os/user/lookup_unix.go:43:35: warning: passing 'gid_t *' (aka 'unsigned int *') to parameter of type 'int *' converts between pointers to integer types with different sign [-Wpointer-sign]<br>
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.11.sdk/usr/include/unistd.h:653:43: note: passing argument to parameter here</p>