gdbm: pass in proper CPPFLAGS (#5893)
gdbm: pass in proper CPPFLAGS (#5893)

The problem was that the configure script was not using spack's compiler
wrappers. We now pass the proper compiler wrapper using the CC argument
explicitly.

Fixes #5892.
matthiasdiener/spack,mfherbst/spack,mfherbst/spack,EmreAtes/spack,mfherbst/spack,tmerrick1/spack,EmreAtes/spack,iulian787/spack,tmerrick1/spack,tmerrick1/spack,iulian787/spack,matthiasdiener/spack,iulian787/spack,krafczyk/spack,krafczyk/spack,skosukhin/spack,EmreAtes/spack,lgarren/spack,lgarren/spack,matthiasdiener/spack,skosukhin/spack,skosukhin/spack,iulian787/spack,krafczyk/spack,matthiasdiener/spack,lgarren/spack,matthiasdiener/spack,tmerrick1/spack,LLNL/spack,LLNL/spack,lgarren/spack,iulian787/spack,mfherbst/spack,LLNL/spack,krafczyk/spack,skosukhin/spack,skosukhin/spack,LLNL/spack,mfherbst/spack,tmerrick1/spack,LLNL/spack,EmreAtes/spack,krafczyk/spack,EmreAtes/spack,lgarren/spack