From 462326afba0395aa28e094e29339b025354af8f7 Mon Sep 17 00:00:00 2001
From: Abhisek Banerjee <bnrjee@amazon.com>
Date: Tue, 20 Oct 2020 23:17:49 +0000
Subject: [PATCH] Support cross compilation only on amd64.

Based on a patch to Bottlerocket by Ben Cressey <bcressey@amazon.com>
https://github.com/bottlerocket-os/bottlerocket/blob/41a72fe21400fa227543fcbed2e59eb0a8b633c1/packages/kubernetes-1.17/0001-always-set-relevant-variables-for-cross-compiling.patch
---
 hack/lib/golang.sh | 52 ++++++++++++++++++++--------------------------
 1 file changed, 23 insertions(+), 29 deletions(-)

diff --git a/hack/lib/golang.sh b/hack/lib/golang.sh
index a96e88e8958f..bef1d837703e 100755
--- a/hack/lib/golang.sh
+++ b/hack/lib/golang.sh
@@ -392,36 +392,30 @@ kube::golang::set_platform_envs() {
 
   export GOOS=${platform%/*}
   export GOARCH=${platform##*/}
-  # Apply standard values for CGO_ENABLED and CC unless KUBE_BUILD_PLATFORMS is set.
-  if [ -z "${KUBE_BUILD_PLATFORMS:-}" ] ; then
-      export CGO_ENABLED=0
-      export CC=gcc
-      return
+
+  # Do not set CC when building natively on a platform, only if cross-compiling from linux/amd64
+  if [[ $(kube::golang::host_platform) == "linux/amd64" ]]; then
+    # Dynamic CGO linking for other server architectures than linux/amd64 goes here
+    # If you want to include support for more server platforms than these, add arch-specific gcc names here
+    case "${platform}" in
+      "linux/arm")
+        export CGO_ENABLED=1
+        export CC=${KUBE_LINUX_ARM_CC:-arm-linux-gnueabihf-gcc}
+        ;;
+      "linux/arm64")
+        export CGO_ENABLED=1
+        export CC=${KUBE_LINUX_ARM64_CC:-aarch64-linux-gnu-gcc}
+        ;;
+      "linux/ppc64le")
+        export CGO_ENABLED=1
+        export CC=${KUBE_LINUX_PPC64LE_CC:-powerpc64le-linux-gnu-gcc}
+        ;;
+      "linux/s390x")
+        export CGO_ENABLED=1
+        export CC=${KUBE_LINUX_S390X_CC:-s390x-linux-gnu-gcc}
+        ;;
+    esac
   fi
-  # Dynamic CGO linking for other server architectures goes here
-  # If you want to include support for more server platforms than these, add arch-specific gcc names here
-  case "${platform}" in
-    "linux/amd64")
-      export CGO_ENABLED=1
-      export CC=${LINUX_AMD64_CC:-gcc}
-      ;;
-    "linux/arm")
-      export CGO_ENABLED=1
-      export CC=${LINUX_ARM_CC:-arm-linux-gnueabihf-gcc}
-      ;;
-    "linux/arm64")
-      export CGO_ENABLED=1
-      export CC=${LINUX_ARM64_CC:-aarch64-linux-gnu-gcc}
-      ;;
-    "linux/ppc64le")
-      export CGO_ENABLED=1
-      export CC=${LINUX_PPC64LE_CC:-powerpc64le-linux-gnu-gcc}
-      ;;
-    "linux/s390x")
-      export CGO_ENABLED=1
-      export CC=${LINUX_S390X_CC:-s390x-linux-gnu-gcc}
-      ;;
-  esac
 }
 
 kube::golang::unset_platform_envs() {