diff -burpN source-original/configure.ac source/configure.ac
--- source-original/configure.ac	2008-11-09 20:12:37.000000000 +0100
+++ source/configure.ac	2018-04-22 23:41:16.945896818 +0200
@@ -85,8 +85,6 @@ if test "$cross_compiling" != "yes"; the
 fi
 
 dnl --- Header files, typedefs, structures
-AC_TYPE_UID_T
-AC_TYPE_SIZE_T
 AC_DECL_SYS_SIGLIST
 AC_HEADER_SYS_WAIT
 AC_CHECK_HEADERS(unistd.h asm/byteorder.h sched.h)
diff -burpN source-original/src/d_deh.c source/src/d_deh.c
--- source-original/src/d_deh.c	2008-10-11 14:10:38.000000000 +0200
+++ source/src/d_deh.c	2018-04-22 23:41:16.949896859 +0200
@@ -54,17 +54,6 @@
 #define TRUE 1
 #define FALSE 0
 
-#ifndef HAVE_STRLWR
-#include <ctype.h>
-
-static char* strlwr(char* str)
-{
-  char* p;
-  for (p=str; *p; p++) *p = tolower(*p);
-  return str;
-}
-#endif
-
 // killough 10/98: new functions, to allow processing DEH files in-memory
 // (e.g. from wads)
 
diff -burpN source-original/src/SDL/i_video.c source/src/SDL/i_video.c
--- source-original/src/SDL/i_video.c	2008-10-18 15:32:29.000000000 +0200
+++ source/src/SDL/i_video.c	2018-04-23 00:51:18.944949507 +0200
@@ -407,7 +407,7 @@ void I_FinishUpdate (void)
     I_UploadNewPalette(newpal);
     newpal = NO_PALETTE_CHANGE;
   }
-  SDL_Flip(screen);
+  SDL_UpdateRect(screen, 0, 0, screen->w, screen->h);
 }
 
 //