Fix the compilation on modern glibc

This should close #12

Author: jvoisin

src/gnuwrapper.cpp

@@ -6,6 +6,8 @@
 
 #ifdef __linux__
 
+#if __GLIBC__ == 2 && __GLIBC_MINOR__ < 34
+
 #ifndef __GNUC__
 #error "This file requires the GNU compiler."
 #endif
@@ -92,4 +94,6 @@ extern "C" {
 
 }
 
+#endif /* __GLIBC__ == 2 && __GLIBC_MINOR__ < 34 */
+
 #endif /* __linux__ */