Fix header generation issues on new GKE clusters

- build: add flex and bison packages to init container
- fix: google container os detection

Co-authored-by: Adelbert Chang <[email protected]>
Co-authored-by: Will Milton <[email protected]>
Co-authored-by: dan <[email protected]>

Author: 3 people

build/Dockerfile.initcontainer

@@ -3,6 +3,8 @@ RUN apk add --update \
     bash \
     bc \
     build-base \
+    bison \
+    flex \
     curl \
     elfutils-dev \
     linux-headers \

build/init/fetch-linux-headers.sh

@@ -56,7 +56,7 @@ fetch_generic_linux_sources()
 install_cos_linux_headers()
 {
   if grep -q CHROMEOS_RELEASE_VERSION "${LSB_FILE}" >/dev/null; then
-    BUILD_ID=$(awk '/CHROMEOS_RELEASE_VERSION =/ { print $3 }' "${LSB_FILE}")
+    BUILD_ID=$(awk '/CHROMEOS_RELEASE_VERSION *= */ { gsub(/^CHROMEOS_RELEASE_VERSION *= */, ""); print }' "${LSB_FILE}")
     BUILD_DIR="/linux-lakitu-${BUILD_ID}"
     SOURCES_DIR="${TARGET_DIR}/linux-lakitu-${BUILD_ID}"
 
@@ -88,7 +88,7 @@ install_generic_linux_headers()
 
 install_headers()
 {
-  distro="$(awk '/^NAME =/ { print $3 }' "${OS_RELEASE_FILE}")"
+  distro="$(awk '/^NAME *= */ { gsub(/^NAME *= */, ""); print }' "${OS_RELEASE_FILE}")"
 
   case $distro in
     *"Container-Optimized OS"*)