I am also having this error, 4.0.6 Ent, PHP 5.2.10, 9 or 8 (only 3 I tried), Centos 5.3 x64
Watching the build process on the machine, it finishes the make (successfully), and then just stops, and never continues to make install.
The phpbuild.sh script in phpbuild just ends with make and...