dthelp: Remove spectaculaly obsolete MSDOS support

cde/programs/dthelp/parser/pass2/build/build.c

@@ -31,9 +31,6 @@ This product and information is proprietary of Tandem Computers Incorporated.
 
 #include <string.h>
 #include <stdlib.h>
-#if defined(MSDOS)
-#include <process.h>
-#endif
 #include "context.h"
 #define BUILDEF
 #include "build.h"

cde/programs/dthelp/parser/pass2/build/out.c

@@ -32,9 +32,6 @@ This product and information is proprietary of Tandem Computers Incorporated.
 #include <string.h>
 #include <stdlib.h>
 #include <ctype.h>
-#if defined(MSDOS)
-#include <process.h>
-#endif
 #include "context.h"
 #include "build.h"
 #include "delim.h"

cde/programs/dthelp/parser/pass2/build/scan.c

@@ -30,9 +30,6 @@ This product and information is proprietary of Tandem Computers Incorporated.
 /* Scan.c contains scanner procedures for program BUILD */
 
 #include <string.h>
-#if defined(MSDOS)
-#include <process.h>
-#endif
 #include "build.h"
 #define M_CONDEF
 #include "context.h"