We are setting one of the flags CFLAGS_JDKLIB, CXXFLAGS_JDKLIB, CFLAGS_JDKEXE or CXXFLAGS_JDKEXE to CFLAGS or CXXFLAGS, respectively, in basically all calls to SetupJdkLibrary and SetupJdkExecutable.

These flag variables contain a lot of duplication.

The first step towards bringing some sanity to this mess is to move the setting of these variables into SetupJdkLibrary/SetupJdkExecutable.

In a few places these standard flags are not set. This is handled by the new arguments `DEFAULT_CFLAGS := false` (to disable the entire setting) and `C[XX]FLAGS_FILTER_OUT` (which excludes some specific flag) to SetupJdkLibrary/SetupJdkExecutable.