gnu: ldc, bap: Build with Clang 3.8.

* gnu/packages/ldc.scm (ldc-bootstrap, ldc): Change LLVM and CLANG to LLVM-3.8
and CLANG-3.8.
* gnu/packages/ocaml.scm (bap)[native-inputs]: Change CLANG to CLANG-3.8.
[propagated-inputs, inputs]: Change LLVM to LLVM-3.8.

gnu/packages/ldc.scm

@@ -138,8 +138,8 @@ and freshness without requiring additional information from the user.")
          ("tzdata" ,tzdata)
          ("zlib" ,zlib)))
       (native-inputs
-       `(("llvm" ,llvm)
-         ("clang" ,clang)
+       `(("llvm" ,llvm-3.8)
+         ("clang" ,clang-3.8)
          ("python-lit" ,python-lit)
          ("python-wrapper" ,python-wrapper)
          ("unzip" ,unzip)
@@ -246,8 +246,8 @@ bootstrapping more recent compilers written in D.")
                       (setenv "CC" (string-append (assoc-ref inputs "gcc") "/bin/gcc"))
                       (invoke "make" "test" "-j" (number->string (parallel-job-count))))))))
       (native-inputs
-       `(("llvm" ,llvm)
-         ("clang" ,clang)
+       `(("llvm" ,llvm-3.8)
+         ("clang" ,clang-3.8)
          ("ldc" ,ldc-bootstrap)
          ("python-lit" ,python-lit)
          ("python-wrapper" ,python-wrapper)

gnu/packages/ocaml.scm

@@ -3494,13 +3494,13 @@ XML and Protocol Buffers formats.")
    (build-system ocaml-build-system)
    (native-inputs
     `(("oasis" ,ocaml-oasis)
-      ("clang" ,clang)
+      ("clang" ,clang-3.8)
       ("ounit" ,ocaml-ounit)))
    (propagated-inputs
     `(("core-kernel" ,ocaml-core-kernel)
       ("ppx-driver" ,ocaml-ppx-driver)
       ("uri" ,ocaml-uri)
-      ("llvm" ,llvm)
+      ("llvm" ,llvm-3.8)
       ("gmp" ,gmp)
       ("clang-runtime" ,clang-runtime)
       ("fileutils" ,ocaml-fileutils)
@@ -3516,7 +3516,7 @@ XML and Protocol Buffers formats.")
       ("bitstring" ,ocaml-bitstring)
       ("ppx-jane" ,ocaml-ppx-jane)
       ("re" ,ocaml-re)))
-   (inputs `(("llvm" ,llvm)))
+   (inputs `(("llvm" ,llvm-3.8)))
    (arguments
     `(#:use-make? #t
       #:phases