Fix --enable-unregistered by passing NOSMP to .hc compiler (#8748)

Signed-off-by: Austin Seipp <austin@well-typed.com>

compiler/ghc.mk

@@ -353,6 +353,11 @@ else
 compiler_CONFIGURE_OPTS += --ghc-option=-DNO_REGS
 endif
 
+ifneq "$(GhcWithSMP)" "YES"
+compiler_CONFIGURE_OPTS += --ghc-option=-DNOSMP
+compiler_CONFIGURE_OPTS += --ghc-option=-optc-DNOSMP
+endif
+
 # Careful optimisation of the parser: we don't want to throw everything
 # at it, because that takes too long and doesn't buy much, but we do want
 # to inline certain key external functions, so we instruct GHC not to