[dnbd3-rootfs] add support for configurable kernel

... version to compile dnbd3 against different kernel then the one
running. Note, this uses the dracut's internal variable storing the
kernel version (specifically '--kver'). This value will be passed to
buid_compile_dnbd3 per environment and injected when calling cmake.

1 files changed, 7 insertions, 1 deletions

diff --git a/builder/modules.d/dnbd3-rootfs/scripts/build.sh b/builder/modules.d/dnbd3-rootfs/scripts/build.sh
index 47e5dcc7..4df163df 100644
--- a/builder/modules.d/dnbd3-rootfs/scripts/build.sh
+++ b/builder/modules.d/dnbd3-rootfs/scripts/build.sh
@@ -81,13 +81,19 @@ build_compile_dnbd3() {
     Examples:
 
     `build_compile_dnbd3 path/to/dnbd3/source/`
+
+    Passing the kernel version to cmake:
+    `CMAKE_FLAGS="-DKERNEL_VERSION=4.14.6-openslx+" \
+        build_compile_dnbd3 path/to/dnbd3/source/`
     '
     pushd "$1"
     # NOTE: The generic way would be: "./build.sh" but this tries to build
     # more than we really need and takes more time.
     mkdir --parents build
     pushd build
-    cmake ../
+    # Inject CMAKE_FLAGS as a way to control how cmake is called,
+    # e.g. to pass the kernel version
+    cmake ${CMAKE_FLAGS} ../
     make -j4 dnbd3 dnbd3-client
     popd
     return $?