win32: make the clang build less crashy

busybox-w32 binaries built using clang crashed so frequently that
they were pretty much unusable.  The main issue seems to be with
assignments to the structures containing global variables which
are used in most applets.

Upstream commit 5156b2455 (Make const ptr assign as function call
in clang) addresses this, but is insufficient for the build on
Windows.  Extend the idea to the ASSIGN_CONST_PTR() macro too.

Costs 32-80 bytes in the gcc build.

1 files changed, 5 insertions, 0 deletions

diff --git a/include/libbb.h b/include/libbb.h
index a7b19b1c9..a469bfe03 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -2439,10 +2439,15 @@ static ALWAYS_INLINE void* not_const_pp(const void *p)
         );
         return pp;
 }
+# if !ENABLE_PLATFORM_MINGW32
 # define ASSIGN_CONST_PTR(pptr, v) do { \
         *(void**)not_const_pp(pptr) = (void*)(v); \
         barrier(); \
 } while (0)
+#else
+/* On Windows it seems necessary for this to be a function too. */
+void ASSIGN_CONST_PTR(const void *pptr, const void *ptr) FAST_FUNC;
+#endif
 /* XZALLOC_CONST_PTR() is an out-of-line function to prevent
  * clang from reading pointer before it is assigned.
  */