Workaround build failure on -fno-common toolchains like upstream
gcc-10. Otherwise build fails as:
ld: raima/startup.o:/build/cde-2.3.2/lib/DtSearch/raima/dbtype.h:408: multiple definition of
`__SK__'; raima/alloc.o:/build/cde-2.3.2/lib/DtSearch/raima/dbtype.h:408: first defined here