Use __APPLE__ instead of OS_MACOS. The former is compiler-provided.

Use __APPLE__ instead of OS_MACOS when testing for the Apple platform and
remove the latter symbol from the BUILD file. This fixes incompatibility issues
when using the library on an Apple device.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=162958094

build_detect_platform

@@ -82,7 +82,7 @@ case "$TARGET_OS" in
         ;;
     Darwin)
         PLATFORM=OS_MACOSX
-        COMMON_FLAGS="$MEMCMP_FLAG -DOS_MACOSX"
+        COMMON_FLAGS="$MEMCMP_FLAG"
         PLATFORM_SHARED_EXT=dylib
         [ -z "$INSTALL_PATH" ] && INSTALL_PATH=`pwd`
         PLATFORM_SHARED_LDFLAGS="-dynamiclib -install_name $INSTALL_PATH/"
@@ -150,7 +150,7 @@ case "$TARGET_OS" in
         ;;
     IOS)
         PLATFORM=IOS
-        COMMON_FLAGS="$MEMCMP_FLAG -DOS_MACOSX"
+        COMMON_FLAGS="$MEMCMP_FLAG"
         [ -z "$INSTALL_PATH" ] && INSTALL_PATH=`pwd`
         PORT_FILE=port/port_posix.cc
         PORT_SSE_FILE=port/port_posix_sse.cc

port/atomic_pointer.h

@@ -25,7 +25,7 @@
 #ifdef OS_WIN
 #include <windows.h>
 #endif
-#ifdef OS_MACOSX
+#ifdef __APPLE__
 #include <libkern/OSAtomic.h>
 #endif
 
@@ -54,7 +54,7 @@ namespace port {
 #define LEVELDB_HAVE_MEMORY_BARRIER
 
 // Mac OS
-#elif defined(OS_MACOSX)
+#elif defined(__APPLE__)
 inline void MemoryBarrier() {
   OSMemoryBarrier();
 }

port/port_posix.h

@@ -8,7 +8,7 @@
 #define STORAGE_LEVELDB_PORT_PORT_POSIX_H_
 
 #undef PLATFORM_IS_LITTLE_ENDIAN
-#if defined(OS_MACOSX)
+#if defined(__APPLE__)
   #include <machine/endian.h>
   #if defined(__DARWIN_LITTLE_ENDIAN) && defined(__DARWIN_BYTE_ORDER)
     #define PLATFORM_IS_LITTLE_ENDIAN \
@@ -50,7 +50,7 @@
 #define PLATFORM_IS_LITTLE_ENDIAN (__BYTE_ORDER == __LITTLE_ENDIAN)
 #endif
 
-#if defined(OS_MACOSX) || defined(OS_SOLARIS) || defined(OS_FREEBSD) ||\
+#if defined(__APPLE__) || defined(OS_SOLARIS) || defined(OS_FREEBSD) ||\
     defined(OS_NETBSD) || defined(OS_OPENBSD) || defined(OS_DRAGONFLYBSD) ||\
     defined(OS_ANDROID) || defined(OS_HPUX) || defined(CYGWIN)
 // Use fread/fwrite/fflush on platforms without _unlocked variants
@@ -59,7 +59,7 @@
 #define fflush_unlocked fflush
 #endif
 
-#if defined(OS_MACOSX) || defined(OS_FREEBSD) ||\
+#if defined(__APPLE__) || defined(OS_FREEBSD) ||\
     defined(OS_OPENBSD) || defined(OS_DRAGONFLYBSD)
 // Use fsync() on platforms without fdatasync()
 #define fdatasync fsync