Compilation errors on Ubuntu 8.04

Running ./configure results in error
error: C compiler cannot create executables

Solution: install package libc-dev (actually libc6-dev is current)

Running ./configure results in
error: C++ preprocessor "/lib/cpp" fails sanity check

Solution: gcc may be installed, but g++ isnt. Install package g++

Running ./configure results in
error: X11 libraries not found

Solution: Install libX11-dev, but in the case of kmail at least, this isnt always what it appears.
kmail makefile was firing this error because qt headers werent available.
Install qt3-dev-tools and threaded qt headers from libqt3-mt-dev