Set NDEBUG when LLVM assertions are disabled

This a component of #36929 which happens to fix building on FreeBSD 11.

Co-authored-by: Keno Fischer <[email protected]>

Author: ararslan

Make.inc

@@ -428,6 +428,10 @@ CXX_DISABLE_ASSERTION := -DJL_NDEBUG
 DISABLE_ASSERTIONS := -DNDEBUG -DJL_NDEBUG
 endif
 
+ifeq ($(LLVM_ASSERTIONS),0)
+CXX_DISABLE_ASSERTION += -DNDEBUG
+endif
+
 # Compiler specific stuff
 
 ifeq ($(USEMSVC), 1)