internal: remove pre-Go 1.18 workaround for reading build info (#2638)

We haven't supported Go 1.17 or older since February 2023, when Go 1.20
was released. So we don't need the workaround for reading debug info
from the binary for pre-Go 1.18 builds.

internal/gitmetadata.go

@@ -8,7 +8,10 @@ package internal
 import (
 	"net/url"
 	"os"
+	"runtime/debug"
 	"sync"
+
+	"gopkg.in/DataDog/dd-trace-go.v1/internal/log"
 )
 
 const (
@@ -73,6 +76,32 @@ func getTagsFromDDTags() map[string]string {
 	}
 }
 
+// getTagsFromBinary extracts git metadata from binary metadata
+func getTagsFromBinary() map[string]string {
+	res := make(map[string]string)
+	info, ok := debug.ReadBuildInfo()
+	if !ok {
+		log.Debug("ReadBuildInfo failed, skip source code metadata extracting")
+		return res
+	}
+	goPath := info.Path
+	var vcs, commitSha string
+	for _, s := range info.Settings {
+		if s.Key == "vcs" {
+			vcs = s.Value
+		} else if s.Key == "vcs.revision" {
+			commitSha = s.Value
+		}
+	}
+	if vcs != "git" {
+		log.Debug("Unknown VCS: '%s', skip source code metadata extracting", vcs)
+		return res
+	}
+	res[TagCommitSha] = commitSha
+	res[TagGoPath] = goPath
+	return res
+}
+
 // GetGitMetadataTags returns git metadata tags
 func GetGitMetadataTags() map[string]string {
 	lock.Lock()