version: refactor get_uname_info()

Some code from "builtin/bugreport.c" uses uname(2) to get system
information.

Let's refactor this code into a new get_uname_info() function, so
that we can reuse it in a following commit.

Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Usman Akinyemi <usmanakinyemi202@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

version.c

@@ -3,6 +3,7 @@
 #include "version-def.h"
 #include "strbuf.h"
 #include "sane-ctype.h"
+#include "gettext.h"
 
 const char git_version_string[] = GIT_VERSION;
 const char git_built_from_commit_string[] = GIT_BUILT_FROM_COMMIT;
@@ -47,3 +48,22 @@ const char *git_user_agent_sanitized(void)
 
 	return agent;
 }
+
+int get_uname_info(struct strbuf *buf)
+{
+	struct utsname uname_info;
+
+	if (uname(&uname_info)) {
+		strbuf_addf(buf, _("uname() failed with error '%s' (%d)\n"),
+			    strerror(errno),
+			    errno);
+		return -1;
+	}
+
+	strbuf_addf(buf, "%s %s %s %s\n",
+		    uname_info.sysname,
+		    uname_info.release,
+		    uname_info.version,
+		    uname_info.machine);
+	return 0;
+}