[SeaBIOS] [PATCH 1/2] docs: Document 'make EXTRAVERSION=xyz'

[Kevin O'Connor]

Document the existence of the EXTRAVERSION field and the information
expected to be present in it.

Signed-off-by: Kevin O'Connor <kevin at koconnor.net>
---
 docs/Build_overview.md | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/docs/Build_overview.md b/docs/Build_overview.md
index 26db226..ac38694 100644
--- a/docs/Build_overview.md
+++ b/docs/Build_overview.md
@@ -52,6 +52,21 @@ CSM_ENABLE'. The SeaBIOS binary will be included as a discrete file
 within the 'Flash Volume' which is created, and there are tools which
 will extract it and allow it to be replaced.
 
+Distribution builds
+===================
+
+If one is building a binary version of SeaBIOS as part of a package
+(such as an rpm) or for wide distribution, please provide the
+EXTRAVERSION field during the build. For example:
+
+`make EXTRAVERSION="-${RPM_PACKAGE_RELEASE}"`
+
+The EXTRAVERSION field should provide the package version (if
+applicable) and the name of the distribution (if that's not already
+obvious from the package version). This string will be appended to the
+main SeaBIOS version. The above information helps SeaBIOS developers
+correlate defect reports to the source code and build environment.
+
 Overview of files in the repository
 ===================================
 
-- 
2.4.3