build: Also pass -fno-strict-aliasing for C++ (#59066)

As diagnosed by Andrew Pinski
(#58466 (comment)),
we are not respecting strict aliasing currently. We turn this off for C,
but the flag appears to be missing for C++. Looks like it's been that
way ever since that flag was first added to our build system (#484). We
should probably consider running TypeSanitizer over our code base to see
if we can make our code correct under strict aliasing as compilers are
increasingly taking advantage of it.

Fixes #58466

Author: Keno

Make.inc

@@ -562,7 +562,7 @@ JCPPFLAGS_COMMON  := -fasynchronous-unwind-tables
 JCPPFLAGS_CLANG   := $(JCPPFLAGS_COMMON) -mllvm -enable-tail-merge=0
 JCPPFLAGS_GCC     := $(JCPPFLAGS_COMMON) -fno-tree-tail-merge
 
-JCXXFLAGS_COMMON  := -pipe $(fPIC) -fno-rtti -std=c++17 -Wformat -Wformat-security
+JCXXFLAGS_COMMON  := -pipe $(fPIC) -fno-rtti -std=c++17 -Wformat -Wformat-security -fno-strict-aliasing
 JCXXFLAGS_CLANG   := $(JCXXFLAGS_COMMON) -pedantic
 JCXXFLAGS_GCC     := $(JCXXFLAGS_COMMON) -fno-gnu-unique