First commit

common/DieWithMessage.c

@@ -0,0 +1,16 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+void DieWithUserMessage(const char *msg, const char *detail) {
+    fputs(msg, stderr);
+    fputs(": ", stderr);
+    fputs(detail, stderr);
+    fputc('\n', stderr);
+    exit(1);
+}
+
+void DieWithSystemMessage(const char *msg) {
+    perror(msg);
+    exit(1);
+}
+