If -DSUITESPARSE_USE_STATIC=ON, then the build system will only look for
static versions of the libraries that are part of SuiteSparse, even if
dynamic/shared versions are present on the system. Thus, the default of
preferring dynamic libraries can be overridden.
SuiteSparse is rarely built ourselves, but still uncommon enough to not
be present on computing clusters.
This patch allows us to install the libraries on a workstation, for
instance from package suitesparse-devel and link to it statically
without having to maintain our own build tree.
The convention is to use uppercase names, in particular our own
./configure script uses this, so we should at least allow it here
(in addition to the old way for backward compatibility)
If we set a default search path ourself, then this will be used if we
specify a SuiteSparse_ROOT with error! Instead, we should just leave
our SuiteSparse_SEARCH_PATH variable empty and then let CMake fill in
its defaults. If there is a directory specified on the other hand
(indicating that we want exactly that location), only use that and
turn all the default paths completely off.
If you test the contents of a variable, this is not necessarily true
in CMake (since the contents here is a path, and not a variable name;
the default test is "does this variable exist", not "is this a non-
empty string" like in shell script)
There is no SuiteSparse headers or libraries in
/System/Library/Frameworks/Accelerate.framework on MacOS X, so adding
this directive won't contribute anything other than compiler warnings.
