libzpool: Set -Wno-error=typedef-redefinition for clang

In some versions of LLVM (at least 21), the <*intrin.h> headers contain
unguarded duplicate typedefs; this isn't permitted prior to C11, and
libzpool is built as C99.  FreeBSD's LLVM backported LLVM PR #153820
to fix this, but other versions of LLVM (e.g., upstream, or on Linux)
don't have the patch, so this breaks the build.

Add -Wno-error=typedef-redefinition to downgrade this from an error
to a warning.

MFC after:	2 weeks
Reviewed by:	dim, emaste
Sponsored by:	https://www.patreon.com/bsdivy
Differential Revision:	https://reviews.freebsd.org/D56653

1 files changed, 5 insertions, 0 deletions

diff --git a/cddl/lib/libzpool/Makefile b/cddl/lib/libzpool/Makefile
index 0c680367956f..db09d33e19b4 100644
--- a/cddl/lib/libzpool/Makefile
+++ b/cddl/lib/libzpool/Makefile
@@ -293,6 +293,11 @@ CFLAGS+=	-g -DDEBUG=1
 
 CFLAGS.gcc+=	-Wno-pointer-to-int-cast
 
+# Some versions of LLVM contain duplicate typedefs in the <*intrin.h> headers,
+# which are not allowed prior to C11; since libzpool is built with C99, make
+# this not be an error.
+CFLAGS.clang+=	-Wno-error=typedef-redefinition
+
 # Pointer values are used as debugging "tags" to mark reference count
 # ownerships and in some cases the tag reference is dropped after an
 # object is freed.