+ I am unable to build suite-sparse@5.2.0 with clang@6.0.0. The build fails
with the error:
```
2397 [ 99%] Linking C executable wildtype_demo
2398 make[4]: Leaving directory
`/tmp/kellyt/spack-stage/spack-stage-w0XYhK/SuiteSparse/GraphBLAS/build'
>> 2399 libgraphblas.so.2.0.1: undefined reference to `__fpclassify'
>> 2400 clang-6.0: error: linker command failed with exit code 1 (use -v to
see invocation)
>> 2401 make[4]: *** [wildtype_demo] Error 1
```
+ This error appears because libgraphblas.so requires `-lm`, but that link
dependency is not explicitly listed in GraphBLAS\CMakeLists.txt.
+ A patch file is provided to add this dependency. The patch is only applied
when the compiler is `%clang`.
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