github: Work around kernel build error

Older versions of the Linux kernel won't compile correctly on newer kernels.
This causes our automated patch checks to fail. This issue has been fixed
upstream but still needs to be applied to some older kernels.

This patch is specifically required to prevent a build failure in the 4.14
kernel that is added in the next commit.

Link: https://lore.kernel.org/selinux/[email protected]/
Signed-off-by: Jason Gerecke <[email protected]>

Author: jigpu

.github/workflows/main.yml

@@ -57,6 +57,12 @@ jobs:
               COMPILER_H=$(ls -v ${KERNELROOT}/include/linux/compiler-gcc*.h | tail -n1)
               ln -s "${COMPILER_H}" "${KERNELROOT}/include/linux/compiler-gcc${GCC_MAJOR_VER}.h"
           fi
+
+          # Fix issue preventing some late-version 4.x kenels from completing config
+          if [[ "${KERNELVER}" == "4."* || "${KERNELVER}" == "5.1" ]]; then
+              curl "https://github.com/torvalds/linux/commit/dfbd199a7cfe3e3cd8531e1353cdbd7175bfbc5e.patch" | patch -t -N -r - -p1 -d "${KERNELROOT}" || true
+          fi
+
           make -C ${KERNELROOT} defconfig
           ${KERNELROOT}/scripts/config --file ${KERNELROOT}/.config --disable UNWINDER_ORC --enable UNWINDER_FRAME_POINTER
           make -C ${KERNELROOT} prepare modules_prepare EXTRA_CFLAGS="${PREPARE_CFLAGS} ${{ matrix.prepare_cflags }}"