Merge branch 'jn/gitweb-install-doc' into maint

* jn/gitweb-install-doc:
  gitweb/INSTALL: GITWEB_CONFIG_SYSTEM is for backward compatibility
  gitweb/INSTALL: Simplify description of GITWEB_CONFIG_SYSTEM

Author: gitster

Documentation/gitweb.conf.txt

@@ -857,6 +857,13 @@ adding the following lines to your gitweb configuration file:
 	$known_snapshot_formats{'zip'}{'disabled'} = 1;
 	$known_snapshot_formats{'tgz'}{'compressor'} = ['gzip','-6'];
 
+BUGS
+----
+Debugging would be easier if the fallback configuration file
+(`/etc/gitweb.conf`) and environment variable to override its location
+('GITWEB_CONFIG_SYSTEM') had names reflecting their "fallback" role.
+The current names are kept to avoid breaking working setups.
+
 ENVIRONMENT
 -----------
 The location of per-instance and system-wide configuration files can be

gitweb/INSTALL

@@ -243,14 +243,11 @@ for gitweb (in gitweb/README), and gitweb.conf(5) manpage.
   GITWEB_CONFIG_SYSTEM build configuration variable, and override it
   through the GITWEB_CONFIG_SYSTEM environment variable.
 
-  Note that if per-instance configuration file exists, then system-wide
-  configuration is _not used at all_.  This is quite untypical and surprising
-  behavior.  On the other hand changing current behavior would break backwards
-  compatibility and can lead to unexpected changes in gitweb behavior.
-  Therefore gitweb also looks for common system-wide configuration file,
-  normally /etc/gitweb-common.conf (set during build time using build time
-  configuration variable GITWEB_CONFIG_COMMON, set it at runtime using
-  environment variable with the same name).  Settings from per-instance or
+  Note that the GITWEB_CONFIG_SYSTEM system-wide configuration file is
+  only used for instances that lack per-instance configuration file.
+  You can use GITWEB_CONFIG_COMMON common system-wide configuration
+  file (normally /etc/gitweb-common.conf) to keep common default
+  settings that apply to all instances.  Settings from per-instance or
   system-wide configuration file override those from common system-wide
   configuration file.