Build Environment prefixes /usr/bin to the PATH variable

The summary basically tells it all.

In the terminal:
$ echo $PATH
/some/local/dir/bin:/usr/lib64/qt4/bin:/usr/lib64/qt-3.3/bin:/usr/local/bin:/usr/bin:/bin

In QtCreator, started from the same terminal, in Projects -> Build settings -> Build Environment:
PATH /usr/bin:/some/local/dir/bin:/usr/lib64/qt4/bin:/usr/lib64/qt-3.3/bin:/usr/local/bin:/usr/bin:/bin

This is for a CMake project that gets loaded through the CMakeLists.txt file. I haven't checked with any of the other types of supported projects.