Restore clang builds in travis.yml

Reviewed-by: NRichard Levitte <levitte@openssl.org>

.travis.yml

@@ -5,13 +5,13 @@ addons:
     apt:
         packages:
             - ccache
-#            - clang-3.6
+            - clang-3.6
             - gcc-5
             - binutils-mingw-w64
             - gcc-mingw-w64
             - wine
         sources:
-#            - llvm-toolchain-precise-3.6
+            - llvm-toolchain-precise-3.6
             - ubuntu-toolchain-r-test
 
 os:
@@ -32,21 +32,17 @@ env:
 matrix:
     include:
         - os: linux
-          compiler: clang
+          compiler: clang-3.6
           env: CONFIG_OPTS="no-shared enable-asan"
-#        - os: linux
-#          compiler: clang-3.6
-#          compiler: clang
-#          env: CONFIG_OPTS="no-shared enable-asan"
-#        - os: linux
-#          compiler: clang-3.6
-#          env: CONFIG_OPTS="no-asm enable-ubsan enable-rc5 enable-md2 -fno-sanitize=alignment"
         - os: linux
-          compiler: gcc-5
-          env: CONFIG_OPTS="no-shared no-asm enable-rc5 enable-md2"
+          compiler: clang-3.6
+          env: CONFIG_OPTS="no-asm enable-ubsan enable-rc5 enable-md2 -fno-sanitize=alignment"
+        - os: linux
+          compiler: clang-3.6
+          env: CONFIG_OPTS="no-shared no-asm enable-asan enable-rc5 enable-md2"
         - os: linux
           compiler: gcc-5
-          env: CONFIG_OPTS="no-asm enable-rc5 enable-md2 -DPEDANTIC"
+          env: CONFIG_OPTS="no-asm enable-ubsan enable-rc5 enable-md2 -DPEDANTIC"
         - os: linux
           compiler: i686-w64-mingw32-gcc
           env: CONFIG_OPTS="no-pic"