Make bionic_malloc.h a platform header.

Instead of having platform directories directly include the
private header, create a platform header directory and export it.

Bug: 130763340

Test: Builds.
Change-Id: Ie0f092b3fe077a3de8b90266c0b28bfbc20d0dfa
Merged-In: Ie0f092b3fe077a3de8b90266c0b28bfbc20d0dfa
(cherry picked from commit 8f582ef2f8a77d953d0e9f33387f592d20f852e2)
diff --git a/libc/malloc_debug/Android.bp b/libc/malloc_debug/Android.bp
index 2bff260..41c4f9d 100644
--- a/libc/malloc_debug/Android.bp
+++ b/libc/malloc_debug/Android.bp
@@ -124,6 +124,10 @@
         "bionic/libc/async_safe/include",
     ],
 
+    header_libs: [
+        "bionic_libc_platform_headers",
+    ],
+
     static_libs: [
         "libc_malloc_debug",
         "libtinyxml2",
@@ -148,7 +152,13 @@
 cc_test {
     name: "malloc_debug_system_tests",
 
-    include_dirs: ["bionic/libc"],
+    include_dirs: [
+        "bionic/libc",
+    ],
+
+    header_libs: [
+        "bionic_libc_platform_headers",
+    ],
 
     srcs: [
         "tests/malloc_debug_system_tests.cpp",