camlp4 -I and shared libs

["Jake Donham" <jake.donham@skydeck.com>]

Hi,

Should the -I flag to camlp4 add the directory to the shared library
search path, as it does with ocamlc?

I was trying to use Micmatch (very nice by the way) with ocamlfind, as follows:

  ocamlfind ocamlc -syntax camlp4o -ppopt pa_micmatch_pcre.cmo
-package micmatch_pcre [...]

but I get an error that it cannot find dllpcre.so. What is happening
is that ocamlfind has pcre-ocaml as a dependency of micmatch_pcre
(even though this is needed only at runtime, not at preprocessing
time), so it adds pcre.cma and -I $SITE_LIB/pcre to the camlp4 command
line. Now pcre.cma needs dllpcre.so, which is in $SITE_LIB/pcre, but
this path is not added to the shared library search path. (It's easy
to work around this by constructing a camlp4 call directly, since
pcre.cma is not needed.)

This is with 3.09.3 but a glance at the 3.10.0 source suggests it has
the same behavior. It's a one-line change (call Dll.add_path after
Dynlink.init in camlp4/odyl/odyl_main.ml or
camlp4/CamlP4/Struct/DynLoader.ml) to fix it.

Thanks,

Jake