libutils: liblog export headers

- make liblog dependency for all library builds (this is required
    for files like String8.cpp)
- export liblog headers (because they are used in many header files).

Test: less libraries fail with BOARD_VNDK_VERSION := current
Merged-In: Iecb9cd00deb3a9056ea63c4a087afdb80a51a2b8
Change-Id: Iecb9cd00deb3a9056ea63c4a087afdb80a51a2b8

libutils/Android.bp

@@ -76,6 +76,13 @@ cc_library {
     header_libs: ["libutils_headers"],
     export_header_lib_headers: ["libutils_headers"],
 
+    shared_libs: [
+        "liblog",
+    ],
+    export_shared_lib_headers: [
+        "liblog",
+    ],
+
     arch: {
         mips: {
             cflags: ["-DALIGN_DOUBLE"],
@@ -97,7 +104,6 @@ cc_library {
                 "libbacktrace",
                 "libcutils",
                 "libdl",
-                "liblog",
             ],
 
             sanitize: {