[Bug c++/34859] New: g++ -D__STDC_LIMIT_MACROS -D__STDC_LIMIT_MACROS causes error

["peeterj at ca dot ibm dot com" <gcc-bugzilla at gcc dot gnu dot org>]

Have a situation where some ugly make recursion is causing -D related cflags
for compilation to be duplicated (only for one file out of thousands)

When that duplication happens to include -D__STDC_LIMIT_MACROS the g++ 4.3
(using 20080111 snapshot) ends up with the following error:

<command-line>: error: "__STDC_LIMIT_MACROS" redefined
<command-line>: error: this is the location of the previous definition

Can reproduce this as follows:

rm -rf r.C
touch r.C
gcc-4.3-20080111/bin/g++ -c -D__STDC_LIMIT_MACROS -D__STDC_LIMIT_MACROS r.C

Other -D values do not appear to cause any sort of trouble.  Example:

gcc-4.3-20080111/bin/g++ -c -D__BLAH -D__BLAH r.C
gcc-4.3-20080111/bin/g++ -c -DXXX -DXXX r.Cvim h

But it appears that duplicate -D statements for anything that starts with
-D__STDC_ causes this error (-D__STDC is okay).

Any explaination for the special casing of the flags that start with __STDC_?

This behaviour has not been observed with g++ 4.2 or lower.


-- 
           Summary: g++ -D__STDC_LIMIT_MACROS -D__STDC_LIMIT_MACROS causes
                    error
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: peeterj at ca dot ibm dot com
 GCC build triplet: x86_64-unknown-linux-gnu
  GCC host triplet: x86_64-unknown-linux-gnu
GCC target triplet: x86_64-unknown-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34859