Spack package update needed to 0.9 release; missing -Wno_narrowing flag in 0.8.1 release

The currently available spack installation for Spindle pulls release 0.8.1 and fails due to narrowing error in compilation of spindle_logd.cc in the logging directory:

    133      CXX    spindle_logd.o
  >> 134    spindle_logd.cc:65:76: error: narrowing conversion of '255' from 'int' to 'char' inside { } [-Wnarrowing]
     135     static char exitcode[8] = { 0x01, 0xff, 0x03, 0xdf, 0x05, 0xbf, 0x07, '\n' };
     136                                                                                ^
  >> 137    spindle_logd.cc:65:76: error: narrowing conversion of '223' from 'int' to 'char' inside { } [-Wnarrowing]
  >> 138    spindle_logd.cc:65:76: error: narrowing conversion of '191' from 'int' to 'char' inside { } [-Wnarrowing]
     139      CCLD   libspindlelogc.la
     140    make[2]: *** [Makefile:386: spindle_logd.o] Error 1
     141    make[2]: Leaving directory '/tmp/asill/spack-stage/spack-stage-spindle-0.8.1-u6g66hhvbkxfa7n32x2gzferzpurspf3/spack-src/logging'
     142    make[1]: *** [Makefile:319: all-recursive] Error 1
     143    make[1]: Leaving directory '/tmp/asill/spack-stage/spack-stage-spindle-0.8.1-u6g66hhvbkxfa7n32x2gzferzpurspf3/spack-src'
     144    make: *** [Makefile:248: all] Error 2

I can work around this by using ./bin/spack install spindle cxxflags="-Wno-narrowing" but likely the spack package should be updated and this flag fixed for the older tarball for manual installations.

Start with the Spack installation entry point in bin/spack and the failing source location logging/spindle_logd.cc. Check how the 0.8.1 package is built and how the 0.9 release is selected. Done means the package targets the requested release and the older tarball builds without the reported narrowing failure.