Fixes STR# 2973: collection of Sun compiler fixes.
                 Applied str_2973_r9979_sun-fix-warnings-7.patch (with small mods)



git-svn-id: http://seriss.com/public/fltk/fltk/branches/branch-1.3@9980 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
Fixes STR# 2973: collection of Sun compiler fixes to Makefiles.
    o Adds $(CXXFLAGS) to $(CXX) commands
    o Implements older, more backwards compatible Bourne shell test(1) syntax for equality tests (= vs ==)



git-svn-id: http://seriss.com/public/fltk/fltk/branches/branch-1.3@9981 ea41ed52-d2ee-0310-a9c1-e6b18d33e121