* ncl: Fix temp directory
Currently, ncl is configured using a transient temp directory. This
leads to warnings such as this when executing ncl later on:
warning:"/tmp/ncl_ncar_xxxxxx" tmp dir does not exist or is not writable:
NCL functionality may be limited -- check TMPDIR environment variable
As this also breaks some functionality, use the system temp directory
instead (typically /tmp).
* ncl: Depend on esmf
esmf is required for some ncl scripts (such as ESMF_regridding.ncl).
Fixes a problem in ymake-filter: The line buffer is currently hardcoded to be
2048 bytes large but some Makefiles contain lines longer than that. This
caused the Makefiles to sometimes not be generated, consequently failing parts
of the build.
* ncl: add depends_on statements for bison, flex and libiconv
* ncl: depends on flex for building and linking
* ncl: links with -ll, so requires flex with variant '+lex'
* ncl: depends on szip; external hdf5 may not provide it
