8335880: More troubleshooting tips around windows space in path

Reviewed-by: erikj, ihse

doc/building.html

@@ -2016,10 +2016,18 @@ some directory names have spaces. Usually, it assumes those directories
 have <a
 href="https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/fsutil-8dot3name">short
 paths</a>. You can run <code>fsutil file setshortname</code> in
-<code>cmd</code> on certain directories, such as
-<code>Microsoft Visual Studio</code> or <code>Windows Kits</code>, to
-assign arbitrary short paths so <code>configure</code> can access
-them.</p>
+<code>cmd</code> on directories to assign arbitrary short paths so
+<code>configure</code> can access them. If the result says "Access
+denied", it may be that there are processes running in that directory;
+in this case, you can reboot Windows in safe mode and run the command on
+those directories again.</p>
+<p>The only directories required to have short paths are
+<code>Microsoft Visual Studio</code> and <code>Windows Kits</code>; the
+rest of the "contains space" warnings from <code>configure</code>, such
+as <code>IntelliJ IDEA</code>, can be ignored. You can choose any short
+name; once it is set, <code>configure</code>'s tools like
+<code>cygpath</code> can convert the directory with spaces to your
+chosen short name and pass it to the build system.</p>
 <h3 id="getting-help">Getting Help</h3>
 <p>If none of the suggestions in this document helps you, or if you find
 what you believe is a bug in the build system, please contact the Build

doc/building.md

@@ -1800,9 +1800,17 @@ temporarily.
 On Windows, when configuring, `fixpath.sh` may report that some directory names
 have spaces. Usually, it assumes those directories have [short
 paths](https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/fsutil-8dot3name).
-You can run `fsutil file setshortname` in `cmd` on certain directories, such as
-`Microsoft Visual Studio` or `Windows Kits`, to assign arbitrary short paths so
-`configure` can access them.
+You can run `fsutil file setshortname` in `cmd` on directories to assign
+arbitrary short paths so `configure` can access them. If the result says "Access
+denied", it may be that there are processes running in that directory; in this
+case, you can reboot Windows in safe mode and run the command on those directories
+again.
+
+The only directories required to have short paths are `Microsoft Visual Studio`
+and `Windows Kits`; the rest of the "contains space" warnings from `configure`,
+such as `IntelliJ IDEA`, can be ignored. You can choose any short name; once it
+is set, `configure`'s tools like `cygpath` can convert the directory with spaces
+to your chosen short name and pass it to the build system.
 
 ### Getting Help