VT port in DOS with Digital Mars compiler : workaround for duplicate getch()es

Both the curses library _and_ the Digital Mars runtime library have a
function called int getch( void).  This patch (which applies _only_ to
the VT port compiled with DMC for DOS) works around that problem.

Author: Bill-Gray

vt/Makefile.dmc

@@ -24,10 +24,9 @@ CC      = dmc
 
 CHTYPE = -DCHTYPE_32
 
-CFLAGS      = -c -o+space -Nc -mld -DDOS
-# CFLAGS      = -c -o+space -Nc -mld -DDOS
+CFLAGS      = -c -o+space -Nc
 
-CPPFLAGS   = -I$(PDCURSES_SRCDIR) -msd $(CHTYPE)
+CPPFLAGS   = -I$(PDCURSES_SRCDIR) -DDOS -mld $(CHTYPE)
 
 LINK      = dmc
 LIBEXE      = lib
@@ -60,7 +59,7 @@ scanw.obj scr_dump.obj scroll.obj slk.obj termattr.obj terminfo.obj \
 touch.obj util.obj window.obj debug.obj
 
 PDCOBJS = pdcclip.obj pdcdisp.obj pdcgetsc.obj pdckbd.obj pdcscrn.obj \
-pdcsetsc.obj pdcutil.obj
+pdcsetsc.obj pdcutil.obj getch2.obj
 
 DEMOOBS    =  calendar.obj firework.obj init_col.obj mbrot.obj \
 newtest.obj ozdemo.obj picsview.obj ptest.obj rain.obj speed.obj \
@@ -225,6 +224,9 @@ pdcsetsc.obj: $(osdir)\pdcsetsc.c
 pdcutil.obj: $(osdir)\pdcutil.c
    $(OSBUILD)
 
+getch2.obj: getch2.c
+   $(OSBUILD)
+
 calendar.exe:   $(demodir)\calendar.c
    $(DEMOBUILD)
 

vt/getch2.c

@@ -0,0 +1,11 @@
+#include <conio.h>
+
+/* Both the curses library and the Digital Mars runtime library have
+functions called int getch( void).   With the following,  code in pdckbd.c
+can call dmc_getch() and get the DMC library version.  It is used _only_
+with Digital Mars; other compilers don't have the name collision.  */
+
+int dmc_getch( )
+{
+   return( _getch( ));
+}

vt/pdckbd.c

@@ -1,4 +1,3 @@
-
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
@@ -15,12 +14,16 @@
 #include "pdcvt.h"
 #include "../common/mouse.c"
 
-#if defined( __BORLANDC__) || defined( DOS)
+#if defined( __BORLANDC__)
    #define WINDOWS_VERSION_OF_KBHIT kbhit
 #else
    #define WINDOWS_VERSION_OF_KBHIT _kbhit
 #endif
 
+#ifdef __DMC__
+   int dmc_getch( void);         /* see 'getch2.c' */
+#endif
+
 /* Modified from the accepted answer at
 
 https://stackoverflow.com/questions/33025599/move-the-cursor-in-a-c-program
@@ -81,7 +84,11 @@ static bool check_key( int *c)
        {
        rval = TRUE;
        if( c)
+#ifdef __DMC__
+          *c = dmc_getch( );         /* see 'getch2.c' */
+#else
           *c = _getch( );
+#endif
        }
     else
        rval = FALSE;