A problem related with installation of gcc 4.2.1?

[Simon King <king at mathematik dot uni-jena dot de>]

Dear gcc-help team,

i'm not sure if the following problem is really due to installation of gcc 
4.2.1, but perhaps you can help me.

1. A while ago, i did successfully build SAGE (some computer algebra 
   system), using gcc 4.1.2. 
2. Later, with your help i succeeded to build gcc 4.2.1.
3. Now, i want to build the new version of SAGE, but it didn't work, 
   neither with gcc 4.2.1 nor 4.1.2.
4. Worse: Now even the old SAGE version does not build, neither with gcc 
   4.1.2 nor 4.2.1, although it did before!

I get the following error message:
  `/usr/local/sage-2.8.5.1/spkg/build/ntl-5.4.1.p5/src/src/small/src'
  ./InitSettings: /usr/lib64/libstdc++.so.6: version `GLIBCXX_3.4.9' not
  found (required by ./InitSettings)

objdump -T showed me that libstdc++.so.6 mentions GLIBCXX_3.4.8, but not 
_3.4.9. Moreover, ls -l showed me that libstdc++.so.6 did not change since 
June 18 --- and the successful sage built was later.

So, from my amateur point of view, the conclusion is that previously only 
GLIBCXX_3.4.8 was expected. 

Do you have an idea how i might have messed these things up? I mean, what 
software is responsible for chosing a version of GLIBCXX?

Note that a google search with "GLIBCXX_3.4.9' not found" yields a lot of 
hits, so it seems to be a common problem. But i did not find any web page 
providing a solution.

Yours sincerely
	Simon