gui-wm/river: fix man build in 0.3.12

Fix: https://bugs.gentoo.org/962978

Signed-off-by: xz-dev <xiangzhedev@gmail.com>
Part-of: https://github.com/gentoo/guru/pull/373
Closes: https://github.com/gentoo/guru/pull/373
Signed-off-by: David Roman <davidroman96@gmail.com>

gui-wm/river/files/river-0.3.12-fix-scdoc-path.patch

@@ -0,0 +1,14 @@
+--- a/build.zig
++++ b/build.zig
+@@ -252,8 +252,9 @@
+         inline for (.{ "river", "riverctl", "rivertile" }) |page| {
+             // Workaround for https://github.com/ziglang/zig/issues/16369
+             // Even passing a buffer to std.Build.Step.Run appears to be racy and occasionally deadlocks.
+-            const scdoc = b.addSystemCommand(&.{ "/bin/sh", "-c", "scdoc < doc/" ++ page ++ ".1.scd" });
++            // Fix: Ensure scdoc runs in the correct source directory to find .scd files
++            const scdoc = b.addSystemCommand(&.{ "/bin/sh", "-c", b.fmt("cd {s} && scdoc < doc/{s}.1.scd", .{ b.build_root.path orelse ".", page }) });
+             // This makes the caching work for the Workaround, and the extra argument is ignored by /bin/sh.
+             scdoc.addFileArg(b.path("doc/" ++ page ++ ".1.scd"));
+
+             const stdout = scdoc.captureStdOut();
+             b.getInstallStep().dependOn(&b.addInstallFile(stdout, "share/man/man1/" ++ page ++ ".1").step);

gui-wm/river/river-0.3.12.ebuild

@@ -49,6 +49,10 @@ RDEPEND="${DEPEND}"
 
 DOCS=( "README.md" )
 
+PATCHES=(
+	"${FILESDIR}/${P}-fix-scdoc-path.patch"
+)
+
 src_configure() {
 	local my_zbs_args=(
 		-Dstrip=false # Let Portage control this