[xen staging] xen/macros: Drop alternative definition of BUILD_BUG_ON(_ZERO)? for old GCC

[patchbot@xxxxxxx]

commit b979189a67637a6a6553ddfb81bea9741bfe9b6a
Author:     Nicola Vetrini <nicola.vetrini@xxxxxxxxx>
AuthorDate: Thu Aug 14 11:36:44 2025 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Thu Aug 14 11:36:44 2025 +0200

    xen/macros: Drop alternative definition of BUILD_BUG_ON(_ZERO)? for old GCC
    
    The toolchain baseline for GCC is 5.1, which supports _Static_assert
    in c99 mode
    
    No functional change.
    
    Signed-off-by: Nicola Vetrini <nicola.vetrini@xxxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/include/xen/macros.h | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/xen/include/xen/macros.h b/xen/include/xen/macros.h
index cd528fbdb1..f9ccde86fb 100644
--- a/xen/include/xen/macros.h
+++ b/xen/include/xen/macros.h
@@ -40,9 +40,6 @@
 
 #ifndef __ASSEMBLY__
 
-/* All clang versions supported by Xen have _Static_assert. */
-#if defined(__clang__) || \
-    (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6))
 /* Force a compilation error if condition is true */
 #define BUILD_BUG_ON(cond) ({ _Static_assert(!(cond), "!(" #cond ")"); })
 
@@ -54,11 +51,6 @@
  */
 #define BUILD_BUG_ON_ZERO(cond) \
     (sizeof(struct { char c; _Static_assert(!(cond), "!(" #cond ")"); }) & 0)
-#else
-#define BUILD_BUG_ON_ZERO(cond) \
-    (sizeof(struct { unsigned u : !(cond); }) & 0)
-#define BUILD_BUG_ON(cond) ((void)BUILD_BUG_ON_ZERO(cond))
-#endif
 
 /*
  * Force a compilation error.  This is for code which, in the normal case,
--
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