crypto: fix build when CGO_ENABLED=0 (ethereum#19121)

Package crypto works with or without cgo, which is great. However, to make it work without cgo required setting the build tag `nocgo`. It's common to disable cgo by instead just setting the environment variable `CGO_ENABLED=0`. Setting this environment variable does _not_ implicitly set the build tag `nocgo`. So projects that try to build the crypto package with `CGO_ENABLED=0` will fail. I have done this myself several times. Until today, I had just assumed that this meant that this package requires cgo. But a small build tag change will make this case work. Instead of using `nocgo` and `!nocgo`, we can use `!cgo` and `cgo`, respectively. The `cgo` build tag is automatically set if cgo is enabled, and unset if it is disabled.
gzliudan · Dec 2, 2024 · 9351308 · 9351308
1 parent 737bb32
commit 9351308
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diff --git a/crypto/signature_cgo.go b/crypto/signature_cgo.go
@@ -14,7 +14,7 @@
 // You should have received a copy of the GNU Lesser General Public License
 // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
 
-// +build !nacl,!js,!nocgo
+// +build !nacl,!js,cgo
 
 package crypto
 

diff --git a/crypto/signature_nocgo.go b/crypto/signature_nocgo.go
@@ -14,7 +14,7 @@
 // You should have received a copy of the GNU Lesser General Public License
 // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
 
-// +build nacl js nocgo
+// +build nacl js !cgo
 
 package crypto