Quoting Ian Lance Taylor <i...@google.com>:
Code that is neither Target Code nor an Independent Module is code that has never been involved with gcc, and the license does not cover it.
There is a lot of Target code that is, per definition, not an Independent Module because it does not use the GCC runtime library.
The license does not prohibit combining Target Code or Independent Modules with other code, so it is permitted.
No, this is not how Copyright works. In the absence of a license you may not distribute the resulting work. So, if you want to combine parts of the GCC runtime library with Independent Modules and other code, your only option (if any) is the GPL. Likewise, if you want to combine any parts of the GCC runtime library which are not Target Code (anything written in assembler is not Target Code, e.g. some targets have crt*.S files) with independent modules, your only option (if any) is the GPL.
