replace ctor with _init

evil/CMakeLists.txt

 add_library(evil SHARED evil.c evil.h)
-set_target_properties(evil PROPERTIES LINK_FLAGS "-s")
+set_target_properties(evil PROPERTIES LINK_FLAGS "-nostartfiles -s")

evil/evil.c

@@ -2,7 +2,7 @@
 
 #include <stdio.h>
 
-void __attribute__((constructor)) init()
+void _init()
 {
     puts("hello, world");
 }

evil/evil.h

 #ifndef LINUX_LIBRARY_INJECT_EVIL_H
 #define LINUX_LIBRARY_INJECT_EVIL_H
 
-void __attribute__((constructor)) init();
+void _init();
 
 #endif  // LINUX_LIBRARY_INJECT_EVIL_H