c/7948: gcc fails to fault gnu extension with -std=c99

[Richard Earnshaw <rearnsha at cambridge dot arm dot com>]

>Number:         7948
>Category:       c
>Synopsis:       gcc fails to fault gnu extension with -std=c99
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    unassigned
>State:          open
>Class:          accepts-illegal
>Submitter-Id:   net
>Arrival-Date:   Tue Sep 17 06:56:01 PDT 2002
>Closed-Date:
>Last-Modified:
>Originator:     Richard Earnshaw
>Release:        3.3 20020917 (experimental)
>Organization:
ARM
>Environment:
System: Linux pc960.cambridge.arm.com 2.4.7-10 #1 Thu Sep 6 17:27:27 EDT 2001 i686 unknown
Architecture: i686

	
host: i686-pc-linux-gnu
build: i686-pc-linux-gnu
target: arm-unknown-elf
configured with: /home/rearnsha/gnusrc/egcs-cross/configure --prefix=/work/rearnsha/gnu/install --disable-checking --target=arm-elf --with-headers=/home/rearnsha/gnusrc/egcs-cross/newlib/libc/include
>Description:
	ISO C99 states that a variable length array may only be used with
	"ordinary identifiers" (ie not structure members).  That makes the
	following code invalid:

	void f(int len)
	{
	  struct {
	    char x[len];
	  } a;
	  /* ... */
	}

	However, gcc accepts this without complaint if the -std=c99 flag is
	used (even if -pedantic is given).

>How-To-Repeat:
	compile the above code fragment with

		gcc -c -std=c99 -pedantic 

	Note that the fragment _is_ correctly rejected if -std=c89 is used.

	
>Fix:
	
>Release-Note:
>Audit-Trail:
>Unformatted: