Makerules: Remove no-op -Wl,-d when linking libc_pic.os

In GNU ld, -d assigns space to common symbols for -r (i.e. change common
symbols to STB_GLOBAL definitions).  This option was added in commit
da2d1bc5 (1998) perhaps because ld at
that time had a bug that common symbols did not override shared object
definitions.  -d has been long unneeded and more so since -fno-common
was added to +cflags.