Clean up use of HAVE_ANDROID_OS

HAVE_ANDROID_OS was defined as "1" for targets, but never defined as "0"
for non-targets. Changing them to #ifdef should be safe and matches
all the other uses of HAVE_ANDROID_OS throughout the system.

Change-Id: I82257325a8ae5e4e4371ddfc4dbf51cea8ea0abb
diff --git a/MemoryHeapBase.cpp b/MemoryHeapBase.cpp
index 624f7eb..9f501e2 100644
--- a/MemoryHeapBase.cpp
+++ b/MemoryHeapBase.cpp
@@ -31,7 +31,7 @@
 
 #include <binder/MemoryHeapBase.h>
 
-#if HAVE_ANDROID_OS
+#ifdef HAVE_ANDROID_OS
 #include <linux/android_pmem.h>
 #endif
 
@@ -108,7 +108,7 @@
 {
     if (size == 0) {
         // try to figure out the size automatically
-#if HAVE_ANDROID_OS
+#ifdef HAVE_ANDROID_OS
         // first try the PMEM ioctl
         pmem_region reg;
         int err = ioctl(fd, PMEM_GET_TOTAL_SIZE, &reg);