liblog: audit declare LIBLOG_ABI_PUBLIC

(cherry pick from commit be1d3c21b57d3e67c6a9682f3b2f0838486a3ee8)

- replace <sys/cdefs.h> with local "log_cdefs.h" which
  fortifies and expands definitions, adding LIBLOG_ABI_PUBLIC,
  LIBLOG_HIDDEN, LIBLOG_ABI_PRIVATE and LIBLOG_WEAK.
- clearly tag each interface as LIBLOG_ABI_PUBLIC, LIBLOG_HIDDEN,
  LIBLOG_ABI_PRIVATE, LIBLOG_WEAK or static depending on scope
- Add -fvisibility=hidden to ensure nothing else leaks
- some code standard adjustments

Bug: 27566046
Change-Id: Ic14033c4e6d833d973beb035ddc1c6134fb35a3f
diff --git a/liblog/Android.mk b/liblog/Android.mk
index dd5b518..6d53a4a 100644
--- a/liblog/Android.mk
+++ b/liblog/Android.mk
@@ -39,7 +39,7 @@
 LOCAL_SRC_FILES_darwin := event_tag_map.c
 LOCAL_SRC_FILES_linux := event_tag_map.c
 LOCAL_SRC_FILES_windows := uio.c
-LOCAL_CFLAGS := -DFAKE_LOG_DEVICE=1 -Werror $(liblog_cflags)
+LOCAL_CFLAGS := -DFAKE_LOG_DEVICE=1 -Werror -fvisibility=hidden $(liblog_cflags)
 LOCAL_MULTILIB := both
 LOCAL_MODULE_HOST_OS := darwin linux windows
 include $(BUILD_HOST_STATIC_LIBRARY)
@@ -59,7 +59,7 @@
 include $(CLEAR_VARS)
 LOCAL_MODULE := liblog
 LOCAL_SRC_FILES := $(liblog_target_sources)
-LOCAL_CFLAGS := -Werror $(liblog_cflags)
+LOCAL_CFLAGS := -Werror -fvisibility=hidden $(liblog_cflags)
 # AddressSanitizer runtime library depends on liblog.
 LOCAL_SANITIZE := never
 include $(BUILD_STATIC_LIBRARY)
@@ -67,7 +67,7 @@
 include $(CLEAR_VARS)
 LOCAL_MODULE := liblog
 LOCAL_WHOLE_STATIC_LIBRARIES := liblog
-LOCAL_CFLAGS := -Werror $(liblog_cflags)
+LOCAL_CFLAGS := -Werror -fvisibility=hidden $(liblog_cflags)
 
 # TODO: This is to work around b/24465209. Remove after root cause is fixed
 LOCAL_LDFLAGS_arm := -Wl,--hash-style=both