Add Features() to retrieve the compile-time features of libgit2

Author: carlosmn

features.go

@@ -0,0 +1,30 @@
+package git
+
+/*
+#include <git2.h>
+*/
+import "C"
+
+type Feature int
+
+const (
+	// libgit2 was built with threading support
+	FeatureThreads Feature = C.GIT_FEATURE_THREADS
+
+	// libgit2 was built with HTTPS support built-in
+	FeatureHttps Feature = C.GIT_FEATURE_HTTPS
+
+	// libgit2 was build with SSH support built-in
+	FeatureSsh Feature = C.GIT_FEATURE_SSH
+
+	// libgit2 was built with nanosecond support for files
+	FeatureNSec Feature = C.GIT_FEATURE_NSEC
+)
+
+// Features returns a bit-flag of Feature values indicating which features the
+// loaded libgit2 library has.
+func Features() Feature {
+	features := C.git_libgit2_features()
+
+	return Feature(features)
+}