configure: Remove probe for _Static_assert

_Static_assert is part of C11, which is now required.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20210614233143.1221879-9-richard.henderson@linaro.org>

configure

@@ -5090,20 +5090,6 @@ if compile_prog "" "" ; then
     have_sysmacros=yes
 fi
 
-##########################################
-# check for _Static_assert()
-
-have_static_assert=no
-cat > $TMPC << EOF
-_Static_assert(1, "success");
-int main(void) {
-    return 0;
-}
-EOF
-if compile_prog "" "" ; then
-    have_static_assert=yes
-fi
-
 ##########################################
 # check for utmpx.h, it is missing e.g. on OpenBSD
 
@@ -6035,10 +6021,6 @@ if test "$have_sysmacros" = "yes" ; then
   echo "CONFIG_SYSMACROS=y" >> $config_host_mak
 fi
 
-if test "$have_static_assert" = "yes" ; then
-  echo "CONFIG_STATIC_ASSERT=y" >> $config_host_mak
-fi
-
 if test "$have_utmpx" = "yes" ; then
   echo "HAVE_UTMPX=y" >> $config_host_mak
 fi

include/qemu/compiler.h

@@ -72,18 +72,7 @@
         int:(x) ? -1 : 1; \
     }
 
-/* QEMU_BUILD_BUG_MSG() emits the message given if _Static_assert is
- * supported; otherwise, it will be omitted from the compiler error
- * message (but as it remains present in the source code, it can still
- * be useful when debugging). */
-#if defined(CONFIG_STATIC_ASSERT)
 #define QEMU_BUILD_BUG_MSG(x, msg) _Static_assert(!(x), msg)
-#elif defined(__COUNTER__)
-#define QEMU_BUILD_BUG_MSG(x, msg) typedef QEMU_BUILD_BUG_ON_STRUCT(x) \
-    glue(qemu_build_bug_on__, __COUNTER__) __attribute__((unused))
-#else
-#define QEMU_BUILD_BUG_MSG(x, msg)
-#endif
 
 #define QEMU_BUILD_BUG_ON(x) QEMU_BUILD_BUG_MSG(x, "not expecting: " #x)