internal/rosa/kmod: prefix moduledir

This change also works around the kernel build system being unaware of this option.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/rosa/kernel.go

@@ -82,6 +82,11 @@ install -Dm0500 \
 echo "Installing linux $1..."
 cp -av "$2" "$4"
 cp -av "$3" "$4"
+`))),
+			pkg.Path(AbsUsrSrc.Append(
+				".depmod",
+			), false, pkg.NewFile("depmod", []byte(`#!/bin/sh
+exec /system/sbin/depmod -m /lib/modules "$@"
 `))),
 		},
 
@@ -1210,6 +1215,11 @@ cgit 1.2.3-korg
 			"all",
 		},
 		Install: `
+# kernel is not aware of kmod moduledir
+install -Dm0500 \
+	/usr/src/.depmod \
+	/sbin/depmod
+
 make \
 	"-j$(nproc)" \
 	-f /usr/src/kernel/Makefile \
@@ -1217,9 +1227,10 @@ make \
 	LLVM=1 \
 	INSTALL_PATH=/work \
 	install \
-	INSTALL_MOD_PATH=/work \
+	INSTALL_MOD_PATH=/work/system \
+	DEPMOD=/sbin/depmod \
 	modules_install
-rm -v /work/lib/modules/` + kernelVersion + `/build
+rm -v /work/system/lib/modules/` + kernelVersion + `/build
 `,
 	},
 		Flex,