https://bugs.gentoo.org/show_bug.cgi?id=409267
http://llvm.org/bugs/show_bug.cgi?id=12334
--- tools/llvm-shlib/Makefile.orig	2012-03-26 18:14:13.071797115 +0200
+++ tools/llvm-shlib/Makefile	2012-03-26 17:31:12.491196254 +0200
@@ -67,6 +67,7 @@
     # Include everything from the .a's into the shared library.
     LLVMLibsOptions := -Wl,--whole-archive $(LLVMLibsOptions) \
                        -Wl,--no-whole-archive
+    LLVMLibsOptions += -Wl,--soname,lib$(LIBRARYNAME)$(SHLIBEXT)
 endif
 
 ifeq ($(HOST_OS),Linux)