[gcc r11-7599] docs: add interactive vs batch distinction to UX guidelines

[David Malcolm]

https://gcc.gnu.org/g:c4a36bb1e1be0b826e71f4723c9f66266aa86b6f

commit r11-7599-gc4a36bb1e1be0b826e71f4723c9f66266aa86b6f
Author: David Malcolm <dmalcolm@redhat.com>
Date:   Wed Mar 10 08:49:29 2021 -0500

    docs: add interactive vs batch distinction to UX guidelines
    
    gcc/ChangeLog:
            * doc/ux.texi: Add subsection contrasting interactive versus
            batch usage of GCC.

Diff:
---
 gcc/doc/ux.texi | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/gcc/doc/ux.texi b/gcc/doc/ux.texi
index fdba5da1598..28d5994d10f 100644
--- a/gcc/doc/ux.texi
+++ b/gcc/doc/ux.texi
@@ -86,6 +86,31 @@ information to allow the user to make an informed choice about whether
 they should care (and how to fix it), but a balance must be drawn against
 overloading the user with irrelevant data.
 
+@subsection Sometimes the user didn't write the code
+
+GCC is typically used in two different ways:
+
+@itemize @bullet
+@item
+Semi-interactive usage: GCC is used as a development tool when the user
+is writing code, as the ``compile'' part of the ``edit-compile-debug''
+cycle.  The user is actively hacking on the code themself (perhaps a
+project they wrote, or someone else's), where they just made a change
+to the code and want to see what happens, and to be warned about
+mistakes.
+
+@item
+Batch rebuilds: where the user is recompiling one or more existing
+packages, and GCC is a detail that's being invoked by various build
+scripts.  Examples include a user trying to bring up an operating system
+consisting of hundreds of packages on a new CPU architecture, where the
+packages were written by many different people, or simply rebuilding
+packages after a dependency changed, where the user is hoping
+``nothing breaks'', since they are unfamiliar with the code.
+@end itemize
+
+Keep both of these styles of usage in mind when implementing diagnostics.
+
 @subsection Precision of Wording
 
 Provide the user with details that allow them to identify what the