warnings in cross-compile of pdcurses are not desired

sys/unix/hints/include/cross-pre.2020

@@ -152,13 +152,14 @@ override TARGET_CC = $(TOOLTOP1)/i586-pc-msdosdjgpp-gcc
 override TARGET_CXX = $(TOOLTOP2)/g++
 override TARGET_AR = $(TOOLTOP1)/i586-pc-msdosdjgpp-gcc-ar
 override TARGET_STUBEDIT = ../lib/djgpp/i586-pc-msdosdjgpp/bin/stubedit
-override TARGET_CFLAGS = -c -O -I../include -I../sys/msdos -I../win/share \
+MSDOS_TARGET_CFLAGS = -c -O -I../include -I../sys/msdos -I../win/share \
 	$(LUAINCL) -DDLB $(PDCURSESDEF) \
 	-DUSE_TILES -DCROSSCOMPILE -DCROSSCOMPILE_TARGET -DCROSS_TO_MSDOS \
         -Wall -Wextra -Wno-missing-field-initializers -Wimplicit \
         -Wreturn-type -Wunused -Wformat -Wswitch -Wshadow -Wwrite-strings \
         -Wimplicit-function-declaration -Wimplicit-int \
-        -Wmissing-declarations -Wmissing-prototypes -Wmissing-parameter-type 
+        -Wmissing-declarations -Wmissing-parameter-type
+override TARGET_CFLAGS = $(MSDOS_TARGET_CFLAGS) -Wmissing-prototypes
 override TARGET_CXXFLAGS = $(TARGET_CFLAGS)
 override TARGET_LINK = $(TOOLTOP1)/i586-pc-msdosdjgpp-gcc
 override TARGET_LFLAGS=
@@ -189,7 +190,7 @@ VARDATND += nhtiles.bmp
 ifdef WANT_WIN_CURSES
 # rules for pdcurses dos-specific files
 $(TARGETPFX)%.o : $(PDCTOP)/dos/%.c
-	$(TARGET_CC) $(PDCINCL) $(TARGET_CFLAGS) -o$@  $<
+	$(TARGET_CC) $(PDCINCL) $(MSDOS_TARGET_CFLAGS) -Wno-unused-parameter -o$@  $<
 endif  # WANT_WIN_CURSES
 #
 # Rule for files in sys/msdos