preprocessor/4824: no macro redef warnings

["Golubev I. N." <gin at mo dot msk dot ru>]

>Number:         4824
>Category:       preprocessor
>Synopsis:       no macro redef warnings
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          accepts-illegal
>Submitter-Id:   net
>Arrival-Date:   Wed Nov 07 09:56:01 PST 2001
>Closed-Date:
>Last-Modified:
>Originator:     Golubev I. N.
>Release:        3.0.2
>Organization:
>Environment:
System: SCO_SV d-fens 3.2 2 i386


host: i586-pc-sco3.2v5.0.2
build: i586-pc-sco3.2v5.0.2
target: i586-pc-sco3.2v5.0.2
configured with:  : (reconfigured)  : (reconfigured) ../gcc-3.0/configure --without-included-gettext --prefix=/usr --with-as=/usr/bin/gas --enable-multilib --disable-static --enable-shared --with-system-zlib --program-transform-name=s/cpp/gcpp/ : (reconfigured) ../gcc-3.0.1/configure --without-included-gettext --prefix=/usr --with-as=/usr/bin/gas --enable-multilib --disable-static --enable-shared --with-system-zlib --program-transform-name=s/cpp/gcpp/ : (reconfigured) ../celesta/gcc-3.0.2/configure --without-included-gettext --prefix=/usr --with-as=/usr/bin/gas --enable-multilib --disable-static --enable-shared --with-system-zlib --program-transform-name=s/cpp/gcpp/ : (reconfigured) ../celesta/gcc-3.0.2/configure --without-included-gettext --prefix=/usr --with-as=/usr/bin/gas --enable-multilib --disable-static --enable-shared --with-system-zlib --program-transform-name=s/cpp/gcpp/
>Description:

I still can not finish gcc build, but I can get gcc programs and
observe the following.  Preprocessor (by default) does not warn about
macro redefinitions.  It is the same in 3.0.1.

>How-To-Repeat:

#define a 1
#define a 2

I expect: warnings like this:

2:warning: `a' redefined
1:warning: this is the location of the previous definition

I get: no warnings.

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