Index: lang/ghc/Makefile
===================================================================
--- lang/ghc/Makefile
+++ lang/ghc/Makefile
@@ -87,7 +87,7 @@
 
 # This version of ncurses is needed by bootstrap compiler
 .if ${OSVERSION} > 1300078 && (${ARCH} == amd64 || ${ARCH} == i386) && empty(PORT_OPTIONS:MBOOT)
-BUILD_DEPENDS=	${LOCALBASE}/lib/compat/libncursesw.so.8:misc/compat12x
+BUILD_DEPENDS+=	${LOCALBASE}/lib/compat/libncursesw.so.8:misc/compat12x
 .endif
 
 .if ${GHC_VERSION_MAJOR} == 8 && ${GHC_VERSION_MINOR} <= 4