From 5dd744b410281739044824e7b0c351b28554759d Mon Sep 17 00:00:00 2001
From: Rebecca Mahany-Horton <rebeccamahany@gmail.com>
Date: Thu, 20 Apr 2023 16:36:52 -0400
Subject: [PATCH] Cross-compile for Linux (#1152)

---
 .github/workflows/go.yml | 9 ++++-----
 Makefile                 | 2 --
 cmd/make/make.go         | 4 ++--
 pkg/make/builder.go      | 3 +++
 4 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/.github/workflows/go.yml b/.github/workflows/go.yml
index 9b3b0e6a3..99aca75d9 100644
--- a/.github/workflows/go.yml
+++ b/.github/workflows/go.yml
@@ -60,14 +60,13 @@ jobs:
     - name: Run govulncheck
       run: go install golang.org/x/vuln/cmd/govulncheck@latest; govulncheck ./...
 
+    - name: Set up zig
+      if: ${{ contains(matrix.os, 'ubuntu') }}
+      uses: goto-bus-stop/setup-zig@v2
+
     - name: Build
-      if: ${{ ! contains(matrix.os, 'ubuntu') }}
       run: make -j2 github-build
 
-    - name: Build (No Cross Compiles)
-      if: ${{ contains(matrix.os, 'ubuntu') }}
-      run: make -j2 github-build-no-cross
-
     - name: Lipo
       run: make github-lipo
       if: ${{ contains(matrix.os, 'macos') }}
diff --git a/Makefile b/Makefile
index a8225e056..08526b96a 100644
--- a/Makefile
+++ b/Makefile
@@ -81,8 +81,6 @@ build/darwin.universal/%: lipo_%
 ##
 GITHUB_TARGETS=launcher grpc.ext tables.ext package-builder
 GITHUB_ARCHS=amd64 arm64
-# linux cross compiles aren't working. Disable for now
-github-build-no-cross: $(foreach t, $(GITHUB_TARGETS), build_$(t))
 github-build: $(foreach t, $(GITHUB_TARGETS), $(foreach a, $(GITHUB_ARCHS), build_$(t)_noop_$(a)))
 github-lipo: $(foreach t, $(GITHUB_TARGETS), lipo_$(t))
 github-launcherapp: $(foreach a, $(GITHUB_ARCHS) universal, build/darwin.$(a)/Kolide.app)
diff --git a/cmd/make/make.go b/cmd/make/make.go
index 39e660f39..f3f0862f9 100644
--- a/cmd/make/make.go
+++ b/cmd/make/make.go
@@ -81,7 +81,7 @@ func main() {
 	// on linux (for fscrypt)
 	optsMaybeCgo := opts
 	if *flBuildOS == "linux" {
-		// overwrite with append, since optsMaybyeCgo was a shallow clone
+		// overwrite with append, since optsMaybeCgo was a shallow clone
 		optsMaybeCgo = append(opts, make.WithCgo())
 	}
 
@@ -91,7 +91,7 @@ func main() {
 		"generate-tuf":    make.New(opts...).GenerateTUF,
 		"launcher":        make.New(optsMaybeCgo...).BuildCmd("./cmd/launcher", fakeName("launcher", *flFakeData)),
 		"tables.ext":      make.New(optsMaybeCgo...).BuildCmd("./cmd/launcher.ext", "tables.ext"),
-		"grpc.ext":        make.New(opts...).BuildCmd("./cmd/grpc.ext", "grpc.ext"),
+		"grpc.ext":        make.New(optsMaybeCgo...).BuildCmd("./cmd/grpc.ext", "grpc.ext"),
 		"package-builder": make.New(opts...).BuildCmd("./cmd/package-builder", "package-builder"),
 		"make":            make.New(opts...).BuildCmd("./cmd/make", "make"),
 	}
diff --git a/pkg/make/builder.go b/pkg/make/builder.go
index a6ddc7cc7..d4668bab2 100644
--- a/pkg/make/builder.go
+++ b/pkg/make/builder.go
@@ -503,6 +503,9 @@ func (b *Builder) BuildCmd(src, appName string) func(context.Context) error {
 		var ldFlags []string
 		if b.static {
 			ldFlags = append(ldFlags, "-d -linkmode internal")
+		} else if b.os == "linux" && b.arch != runtime.GOARCH {
+			// Cross-compiling for Linux requires external linking
+			ldFlags = append(ldFlags, "-linkmode external")
 		}
 
 		if !b.notStripped {