http://www.mozilla.org/ports/os2/
March 22, 2006 The required GCC runtime library for trunk and 1.8 branch builds has been updated to version 0.6.1, which supercedes 0.6 and can be used with all builds requiring version 0.6.
ftp://ftp.netlabs.org/pub/gcc/libc-0.6.1-csd1.zip
Source: OS2VOICE