If we have new features introduced by C11, use them

Instead of using hacks or compiler-specific features, if we have
standard features as defined in ISO C11, use them.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

include/compiler.h

@@ -77,6 +77,7 @@
 # include "nasmint.h"
 #endif
 
+#include <assert.h>
 #include <stddef.h>
 #include <stdarg.h>
 #include <stdio.h>
@@ -208,7 +209,10 @@ char *strsep(char **, const char *);
 /*
  * How to tell the compiler that a function doesn't return
  */
-#ifdef HAVE_FUNC_ATTRIBUTE_NORETURN
+#ifdef HAVE_STDNORETURN_H
+# include <stdnoreturn.h>
+# define no_return noreturn void
+#elif defined(HAVE_FUNC_ATTRIBUTE_NORETURN)
 # define no_return void __attribute__((noreturn))
 #else
 # define no_return void

include/nasmlib.h

@@ -175,7 +175,18 @@ no_return nasm_assert_failed(const char *, int, const char *);
 /*
  * NASM failure at build time if x != 0
  */
-#define nasm_build_assert(x) (void)(sizeof(char[1-2*!!(x)]))
+#ifdef static_assert
+# define nasm_build_assert(x) static_assert(x, "assertion " #x " failed")
+#elif defined(HAVE_FUNC_ATTRIBUTE_ERROR)
+# define nasm_build_assert(x)                                           \
+    if (!(x)) {                                                         \
+        extern void __attribute__((error("assertion " #x " failed")))      \
+            fail(void);                                                 \
+        fail();                                                         \
+    }
+#else
+# define nasm_build_assert(x) (void)(sizeof(char[1-2*!(x)]))
+#endif
 
 /*
  * ANSI doesn't guarantee the presence of `stricmp' or