diff --git a/src/c_screen.cpp b/src/c_screen.cpp
index 7c25b48c..f46ecb6b 100644
--- a/src/c_screen.cpp
+++ b/src/c_screen.cpp
@@ -126,7 +126,7 @@ static int init(FILE *f, int o, int now)
     else
         return CON_INIT;
 
-#if defined(__DJGPP__)
+#if (ACC_OS_DOS32) && defined(__DJGPP__)
     if (!screen)
         screen = do_construct(screen_djgpp2_construct(),fd);
 #endif
diff --git a/src/conf.h b/src/conf.h
index e28a5ee4..484bfe50 100644
--- a/src/conf.h
+++ b/src/conf.h
@@ -123,7 +123,7 @@ typedef unsigned char   upx_byte;
 #undef small
 #undef tos
 #undef unix
-#if defined(__DJGPP__)
+#if (ACC_OS_DOS32) && defined(__DJGPP__)
 #  undef sopen
 #  undef __unix__
 #  undef __unix
diff --git a/src/console.h b/src/console.h
index bbe9c88a..8dc87fc0 100644
--- a/src/console.h
+++ b/src/console.h
@@ -56,7 +56,7 @@
 #  endif
 #endif
 
-#if 1 && defined(__DJGPP__)
+#if 1 && (ACC_OS_DOS32) && defined(__DJGPP__)
 #  define USE_SCREEN 1
 #elif 1 && (ACC_OS_CYGWIN || ACC_OS_WIN32 || ACC_OS_WIN64)
 #  define USE_SCREEN 1
diff --git a/src/file.cpp b/src/file.cpp
index af232492..7612829e 100644
--- a/src/file.cpp
+++ b/src/file.cpp
@@ -48,7 +48,7 @@ void File::chmod(const char *name, int mode)
 
 void File::rename(const char *old_, const char *new_)
 {
-#if defined(__DJGPP__)
+#if (ACC_OS_DOS32) && defined(__DJGPP__)
     if (::_rename(old_,new_) != 0)
 #else
     if (::rename(old_,new_) != 0)
@@ -94,7 +94,7 @@ bool FileBase::do_sopen()
         _fd = ::open(_name, _flags, _mode);
     else
     {
-#if defined(__DJGPP__)
+#if (ACC_OS_DOS32) && defined(__DJGPP__)
         _fd = ::open(_name,_flags | _shflags, _mode);
 #elif defined(__MINT__)
         _fd = ::open(_name,_flags | (_shflags & O_SHMODE), _mode);
diff --git a/src/help.cpp b/src/help.cpp
index d77bc69c..568cb318 100644
--- a/src/help.cpp
+++ b/src/help.cpp
@@ -91,7 +91,7 @@ void show_usage(void)
     FILE *f = con_term;
 
     con_fprintf(f,"Usage: %s [-123456789dlthVL] [-qvfk] [-o file] %sfile..\n", progname,
-#if defined(__DJGPP__) || defined(__EMX__)
+#if (ACC_OS_DOS32) && defined(__DJGPP__)
                 "[@]");
 #else
                 "");
diff --git a/src/main.cpp b/src/main.cpp
index 5d87877f..b2c3d93b 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -33,7 +33,7 @@
 #include "p_elf.h"
 
 
-#if 1 && defined(__DJGPP__)
+#if 1 && (ACC_OS_DOS32) && defined(__DJGPP__)
 #include <crt0.h>
 int _crt0_startup_flags = _CRT0_FLAG_UNIX_SBRK;
 #endif
@@ -61,7 +61,7 @@ void options_t::reset()
     o->preserve_timestamp = true;
 
     o->console = CON_FILE;
-#if defined(__DJGPP__)
+#if (ACC_OS_DOS32) && defined(__DJGPP__)
     o->console = CON_INIT;
 #elif (USE_SCREEN_WIN32)
     o->console = CON_INIT;
@@ -1413,7 +1413,7 @@ int __acc_cdecl_main main(int argc, char *argv[])
     static char default_argv0[] = "upx";
 //    int cmdline_cmd = CMD_NONE;
 
-#if 0 && defined(__DJGPP__)
+#if 0 && (ACC_OS_DOS32) && defined(__DJGPP__)
     // LFN=n may cause problems with 2.03's _rename and mkdir under WinME
     putenv("LFN=y");
 #endif
diff --git a/src/packer.cpp b/src/packer.cpp
index b4e83b3c..bdc3e63d 100644
--- a/src/packer.cpp
+++ b/src/packer.cpp
@@ -638,7 +638,7 @@ unsigned Packer::getRandomId() const
 #endif
     while (id == 0)
     {
-#if !(HAVE_GETTIMEOFDAY) || defined(__DJGPP__)
+#if !(HAVE_GETTIMEOFDAY) || ((ACC_OS_DOS32) && defined(__DJGPP__))
         id ^= (unsigned) time(NULL);
         id ^= ((unsigned) clock()) << 12;
 #else
diff --git a/src/s_djgpp2.cpp b/src/s_djgpp2.cpp
index 3808c8fe..365ded1a 100644
--- a/src/s_djgpp2.cpp
+++ b/src/s_djgpp2.cpp
@@ -27,7 +27,10 @@
 
 #include "conf.h"
 
-#if (USE_SCREEN) && defined(__DJGPP__)
+#if (USE_SCREEN) && (ACC_OS_DOS32) && defined(__DJGPP__)
+#if (ACC_CC_GNUC >= 0x040300ul)
+#pragma GCC diagnostic ignored "-Wvla"
+#endif
 
 #include "screen.h"
 
@@ -248,7 +251,7 @@ static int init(screen_t *this, int fd) {
     if (getPage(this) != 0)
         return -1;
 
-#if 1 && defined(__DJGPP__)
+#if 1 && (ACC_OS_DOS32) && defined(__DJGPP__)
     /* check for Windows NT/2000/XP */
     if (_get_dos_version(1) == 0x0532)
         return -1;
@@ -432,6 +435,6 @@ static const screen_t driver = {sobject_destroy, 0, /* finalize, */
 /* public constructor */
 screen_t *screen_djgpp2_construct(void) { return sobject_construct(&driver, sizeof(*driver.data)); }
 
-#endif /* (USE_SCREEN) && defined(__DJGPP__) */
+#endif /* (USE_SCREEN) && (ACC_OS_DOS32) && defined(__DJGPP__) */
 
 /* vim:set ts=4 sw=4 et: */
diff --git a/src/ui.cpp b/src/ui.cpp
index e3da0983..f01b7442 100644
--- a/src/ui.cpp
+++ b/src/ui.cpp
@@ -105,7 +105,7 @@ static void init_global_constants(void) {
         return;
     done = true;
 
-#if 1 && defined(__DJGPP__)
+#if 1 && (ACC_OS_DOS32) && defined(__DJGPP__)
     /* check for Windows NT/2000/XP */
     if (_get_dos_version(1) == 0x0532)
         return;
diff --git a/src/util.cpp b/src/util.cpp
index 265b5a78..3383614e 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -587,24 +587,14 @@ extern "C" {
 int dup(int fd) { UNUSED(fd); return -1; }
 #endif
 
-#if defined(__DJGPP__)
-int _is_executable(const char *, int, const char *)
-{
-    return 0;
-}
+#if (ACC_OS_DOS32) && defined(__DJGPP__)
+//int _is_executable(const char *, int, const char *) { return 0; }
 
 // FIXME: something wants to link in ctime.o
-time_t XXX_mktime(struct tm *)
-{
-    return 0;
-}
+//time_t mktime(struct tm *) { return 0; }
 
-time_t time(time_t *t)
-{
-    if (t) *t = 0;
-    return 0;
-}
-#endif /* __DJGPP__ */
+//time_t time(time_t *t) { if (t) *t = 0; return 0; }
+#endif
 
 
 } // extern "C"
diff --git a/src/work.cpp b/src/work.cpp
index 695875f1..a98726b9 100644
--- a/src/work.cpp
+++ b/src/work.cpp
@@ -33,7 +33,7 @@
 #include "ui.h"
 
 
-#if defined(__DJGPP__)
+#if (ACC_OS_DOS32) && defined(__DJGPP__)
 #  define USE_FTIME 1
 #elif (ACC_OS_WIN32 && ACC_CC_MWERKS) && defined(__MSL__)
 #  include <utime.h>