Bug#848368: llvm-toolchain-3.9: Please add ELF symbols versions to the libraries

[Rebecca N. Palmer]

12 clang tests "unexpectedly" fail, but they're the same 12 that do so 
in the existing package:
Failing Tests (12):
     Clang :: CodeGen/linux-arm-atomic.c
     Clang :: Driver/arm-cortex-cpus.c
     Clang :: Driver/arm-features.c
     Clang :: Driver/arm-ias-Wa.s
     Clang :: Driver/arm-mfpu.c
     Clang :: Driver/cross-linux.c
     Clang :: Driver/mips-as.c
     Clang :: Driver/mips-integrated-as.s
     Clang :: Preprocessor/arm-acle-6.5.c
     Clang :: Preprocessor/arm-target-features.c
     Clang :: Sema/builtins.c
     Clang :: SemaCXX/warn-memsize-comparison.cpp

   Expected Passes    : 9572
   Expected Failures  : 16
   Unsupported Tests  : 40
   Unexpected Failures: 12

The build then fails for symbols mismatch...with what looks like exactly 
the change we *want*:

(last few of many)
+ clang_saveTranslationUnit at LLVM_3.9 1:3.9.1-5local2
+#MISSING: 1:3.9.1-5local2# clang_sortCodeCompletionResults at Base 3.2
+ clang_sortCodeCompletionResults at LLVM_3.9 1:3.9.1-5local2
+#MISSING: 1:3.9.1-5local2# clang_toggleCrashRecovery at Base 3.2
+ clang_toggleCrashRecovery at LLVM_3.9 1:3.9.1-5local2
+#MISSING: 1:3.9.1-5local2# clang_tokenize at Base 3.2
+ clang_tokenize at LLVM_3.9 1:3.9.1-5local2
+#MISSING: 1:3.9.1-5local2# clang_visitChildren at Base 3.2
+ clang_visitChildren at LLVM_3.9 1:3.9.1-5local2
+#MISSING: 1:3.9.1-5local2# clang_visitChildrenWithBlock at Base 3.2
+ clang_visitChildrenWithBlock at LLVM_3.9 1:3.9.1-5local2
dh_makeshlibs: failing due to earlier errors