Revert "compiler: Add fallthrough() helper"

This reverts commit 8ba28e13ea.

aclocal.m4

@@ -199,29 +199,3 @@ inline int foo(int x)
     [Define to 1 if your compiler supports C99 extern inline])],
  [AC_MSG_RESULT([no])
   PA_ADD_CFLAGS([-fgnu89-inline])])])
-
-dnl --------------------------------------------------------------------------
-dnl PA_CHECK_FALLTHROUGH_ATTRIBUTE
-dnl --------------------------------------------------------------------------
-AC_DEFUN(PA_CHECK_FALLTHROUGH_ATTRIBUTE,
-[AC_MSG_CHECKING([if $CC supports fallthrough attribute])
- AC_COMPILE_IFELSE([AC_LANG_SOURCE([
-AC_INCLUDES_DEFAULT
-int main(int argc, char **argv)
-{
-	switch (argc) {
-	case 1:
-		(void)argc;
-		__attribute__((fallthrough));
-	default:
-		(void)argv;
-		break;
-	}
-	return argc;
-}
- ])],
- [AC_MSG_RESULT([yes])
-  AC_DEFINE([HAVE_FALLTHROUGH_ATTRIBUTE], 1,
-    [Define to 1 if your compiler supports __attribute__((fallthrough))])],
- [AC_MSG_RESULT([no])])
-])

configure.ac

@@ -294,11 +294,6 @@ dnl options.
 dnl
 PA_CHECK_BAD_STDC_INLINE
 
-dnl Figure out if we can use fallthrough attribute or
-dnl should provide simple comment instead.
-dnl
-PA_CHECK_FALLTHROUGH_ATTRIBUTE
-
 dnl
 dnl support ccache
 dnl

include/compiler.h

@@ -240,15 +240,6 @@ size_t strnlen(const char *s, size_t maxlen);
 # define inline_prototypes
 #endif
 
-/*
- * Fallthrough handling.
- */
-#ifdef HAVE_FALLTHROUGH_ATTRIBUTE
-# define fallthrough() __attribute__((fallthrough))
-#else
-# define fallthrough() /* fall through */
-#endif
-
 /*
  * Hints to the compiler that a particular branch of code is more or
  * less likely to be taken.