Fix libutils_binder_sdk build warnings

-Wclass-memaccess
-Winvalid-offsetof
-Wsequence-point
-Wzero-as-null-pointer-constant (turned on in ag/4503295)

Bug: 285204695
Test: m libutils_binder_sdk
Change-Id: I5b988f498cb8e0cf04617a4f7fd41ba9970d321d
diff --git a/libutils/binder/SharedBuffer.cpp b/libutils/binder/SharedBuffer.cpp
index 3e703db..d16bdb0 100644
--- a/libutils/binder/SharedBuffer.cpp
+++ b/libutils/binder/SharedBuffer.cpp
@@ -75,7 +75,7 @@
         LOG_ALWAYS_FATAL_IF((newSize >= (SIZE_MAX - sizeof(SharedBuffer))),
                             "Invalid buffer size %zu", newSize);
 
-        buf = (SharedBuffer*)realloc(buf, sizeof(SharedBuffer) + newSize);
+        buf = (SharedBuffer*)realloc(reinterpret_cast<void*>(buf), sizeof(SharedBuffer) + newSize);
         if (buf != nullptr) {
             buf->mSize = newSize;
             return buf;