Document which version of glibc the integration requires

Currently, it looks like the Qt Eclipse integration for Linux, version 1.4.3, requires different versions of glibc for 32-bit and 64-bit:

strings eclipse/plugins/com.trolltech.qtcpp.linux.x86_4.4.2/lib/libQtScriptCppIntegration.so.4.4.2 | grep GLIBC
GLIBCXX_3.4
GLIBC_2.1.3
GLIBC_2.0

strings eclipse/plugins/com.trolltech.qtcpp.linux.x86_64_4.4.2/lib/libQtScriptCppIntegration.so.4.4.2 | grep GLIBC
GLIBCXX_3.4
GLIBC_2.4
GLIBC_2.2.5

This should probably be documented, in the same way we document which gcc version was used to build the different integration packages.