Build the linker with -D_USING_LIBCXX
This macro is necessary for using stdatomic.h and <atomic> in the same
libc++-based program. <atomic> is used implicitly by other STL headers,
and stdatomic.h is used (or will be used) in headers shared with libc.
libc only has access to stdatomic.h because it can't use an STL.
Bug: http://b/78026329
Test: bionic unit tests
Change-Id: I89b128df08b478287ef4e2867319e74dbcc30d4e
diff --git a/linker/Android.bp b/linker/Android.bp
index 38a53f8..e103ade 100644
--- a/linker/Android.bp
+++ b/linker/Android.bp
@@ -176,6 +176,11 @@
"-Wextra",
"-Wunused",
"-Werror",
+
+ // Define _USING_LIBCXX so <stdatomic.h> defers to the <atomic> header. When a Soong module
+ // uses the platform libc++, Soong automatically passes this macro, but the dynamic linker
+ // links against libc++ manually.
+ "-D_USING_LIBCXX",
],
// TODO: split out the asflags.
