0.3.0: converge relibc to upstream 0.6.0 + Red Bear patches

tests/sharedlib.c

@@ -0,0 +1,10 @@
+#include <stdio.h>
+
+int global_var = 42;
+_Thread_local int tls_var = 21;
+
+void print()
+{
+    fprintf(stdout, "sharedlib: global_var == %d\n", global_var);
+    fprintf(stdout, "sharedlib: tls_var == %d\n", tls_var);
+}