Speed up win-ldd by not reading the full output of objdump

We can stop after the import table dump is done. We don't need to read
the entire relocation table and the export table.

Signed-off-by: Thiago Macieira <thiago@macieira.org>
Disable the code that tries to find an alternate objdump

On Linux distros, it seems, objdump is configured to read Windows
executables (BFD architecture "pei-i386"), so we don't need to find an
alternate / cross-compile version. But leave the code here in case we
run into a distro that does things differently.

Signed-off-by: Thiago Macieira <thiago@macieira.org>
Use the $PATH environment variable to pass extra dirs for DLLs

Unix developers, look away... this is how it's done on Windows: the
binary loader searches $PATH for the DLLs, so let's reuse the same
variable. This simplifies the command-line a little.

Signed-off-by: Thiago Macieira <thiago@macieira.org>
Add support for parsing more than one binary in win-ldd

We're going to need this to deploy Qt and Marble plugins.

Signed-off-by: Thiago Macieira <thiago@macieira.org>
Deploy some Qt plugins alongside the binary

Only implemented for Windows for now. On Mac, macdeployqt copies all
imageformat plugins on its own.

Signed-off-by: Thiago Macieira <thiago@macieira.org>