more ANSI/ISO C changes; start on converting the unwind-protect framework to ANSI C

include/memalloc.h

@@ -46,11 +46,7 @@
 #    endif /* !IBMESA */
 #  else  /* !HAVE_ALLOCA_H || C_ALLOCA */
 #    if !defined (alloca)
-#      if defined (__STDC__)
 extern void *alloca (size_t);
-#      else
-extern char *alloca ();
-#      endif /* !__STDC__ */
 #    endif /* !alloca */
 #  endif /* !HAVE_ALLOCA_H || C_ALLOCA */
 #endif /* !__GNUC__ || C_ALLOCA */

include/stdc.h

@@ -1,7 +1,7 @@
 /* stdc.h -- macros to make source compile on both ANSI C and K&R C
    compilers. */
 
-/* Copyright (C) 1993-2021 Free Software Foundation, Inc.
+/* Copyright (C) 1993-2021,2023 Free Software Foundation, Inc.
 
    This file is part of GNU Bash, the Bourne Again SHell.
 
@@ -86,10 +86,4 @@
 #  define INLINE
 #endif
 
-#if defined (PREFER_STDARG)
-#  define SH_VA_START(va, arg)  va_start(va, arg)
-#else
-#  define SH_VA_START(va, arg)  va_start(va)
-#endif
-
 #endif /* !_STDC_H_ */