build: install example config to /etc/river/init

 build.zig                         | 8 ++++++++
 contrib/config.sh => example/init | 7 +++++++
 2 files changed, 15 insertions(+)

diff --git a/build.zig b/build.zig
index 0f46824..62f4afc 100644
--- a/build.zig
+++ b/build.zig
@@ -27,6 +27,14 @@ pub fn build(b: *zbs.Builder) !void {
 
     const examples = b.option(bool, "examples", "Set to true to build examples") orelse false;
 
+    // Sigh, why are the conventions inconsistent like this.
+    const resolved_prefix = try std.fs.path.resolve(b.allocator, &[_][]const u8{b.install_prefix.?});
+    if (std.mem.eql(u8, resolved_prefix, "/usr")) {
+        b.installFile("example/init", "../etc/river/init");
+    } else {
+        b.installFile("example/init", "etc/river/init");
+    }
+
     const scanner = ScanProtocolsStep.create(b);
     scanner.addSystemProtocol("stable/xdg-shell/xdg-shell.xml");
     scanner.addProtocolPath("protocol/river-control-unstable-v1.xml");
diff --git a/contrib/config.sh b/example/init
similarity index 95%
rename from contrib/config.sh
rename to example/init
index c5f3969..879aaa1 100755
--- a/contrib/config.sh
+++ b/example/init
@@ -1,5 +1,12 @@
 #!/bin/sh
 
+# This is the example configuration file for river(1).
+#
+# If you wish to edit this, you will probably want to copy it to
+# $XDG_CONFIG_HOME/river/init or $HOME/.config/river/init first.
+#
+# See the riverctl(1) man page for complete documentation
+
 # Use the "logo" key as the primary modifier
 mod="Mod4"