CMake flags set at the superbuild level are not propagated to dcmqi-build inner target

[fedorov]

@jcfr as discussed in #247, flags set at cmake configure time for the top-level project are not propagated into dcmqi target. This looks like a bug to me.

[fedorov]

Specific example.

Flags passed to cmake at the superbuild level:

$ cmake -DCMAKE_CXX_FLAGS="-g -O0 -fprofile-arcs -ftest-coverage"       
  -DCMAKE_C_FLAGS="-g -O0 -fprofile-arcs -ftest-coverage"       
  -DCMAKE_EXE_LINKER_FLAGS="-fprofile-arcs -ftest-coverage"       
  -DCMAKE_MODULE_LINKER_FLAGS="-fprofile-arcs -ftest-coverage"       
  -DCMAKE_SHARED_LINKER_FLAGS="-fprofile-arcs -ftest-coverage" ..

Flags visible in ccmake at the superbuild level:

Flags in dcmqi-build inner build directory:

[fedorov]

Workaround for this specific situation: set env variables CFLAGS, CXXFLAGS, LDFLAGS.