Remove: DOS support

In 10 years there was no active development on DOS. Although it
turned out to still work, the FPS was very bad. There is little
interest in the current community to look into this.

Further more, we like to switch to c++11 functions for threads,
which are not implemented by DJGPP, the only current compiler
for DOS.

Additionally, DOS is the only platform which does not support
networking. It is the reason we have tons of #ifdefs to support
disabling networking.

By removing DOS support, we can both use c++11 functions for threads,
and remove all the code related to disabling network. Sadly, this
means we have to see DOS go.

Of course, if you feel up for the task, simply revert this commit,
and implement stub c++11 functions for threads and stub functions
for networking. We are more than happy to accept such Pull Request.

1 files changed, 14 insertions, 22 deletions

diff --git a/config.lib b/config.lib
index bab1ca4ea..18ea119c4 100644
--- a/config.lib
+++ b/config.lib
@@ -553,10 +553,10 @@ check_params() {
 
 	# Check if all params have valid values
 
-	# OS only allows DETECT, UNIX, OSX, FREEBSD, DRAGONFLY, OPENBSD, NETBSD, HAIKU, SUNOS, CYGWIN, MINGW, OS2, and DOS
-	if [ -z "`echo $os | egrep '^(DETECT|UNIX|OSX|FREEBSD|DRAGONFLY|OPENBSD|NETBSD|HPUX|HAIKU|SUNOS|CYGWIN|MINGW|OS2|DOS)$'`" ]; then
+	# OS only allows DETECT, UNIX, OSX, FREEBSD, DRAGONFLY, OPENBSD, NETBSD, HAIKU, SUNOS, CYGWIN, MINGW, and OS2
+	if [ -z "`echo $os | egrep '^(DETECT|UNIX|OSX|FREEBSD|DRAGONFLY|OPENBSD|NETBSD|HPUX|HAIKU|SUNOS|CYGWIN|MINGW|OS2)$'`" ]; then
 		log 1 "configure: error: invalid option --os=$os"
-		log 1 " Available options are: --os=[DETECT|UNIX|OSX|FREEBSD|DRAGONFLY|OPENBSD|NETBSD|HPUX|HAIKU|SUNOS|CYGWIN|MINGW|OS2|DOS]"
+		log 1 " Available options are: --os=[DETECT|UNIX|OSX|FREEBSD|DRAGONFLY|OPENBSD|NETBSD|HPUX|HAIKU|SUNOS|CYGWIN|MINGW|OS2]"
 		exit 1
 	fi
 	# cpu_type can be either 32 or 64
@@ -623,7 +623,7 @@ check_params() {
 	detect_sse_capable_architecture
 
 	if [ "$enable_static" = "1" ]; then
-		if [ "$os" = "MINGW" ] || [ "$os" = "CYGWIN" ] || [ "$os" = "DOS" ]; then
+		if [ "$os" = "MINGW" ] || [ "$os" = "CYGWIN" ]; then
 			enable_static="2"
 		else
 			enable_static="0"
@@ -633,8 +633,8 @@ check_params() {
 	if [ "$enable_static" != "0" ]; then
 		log 1 "checking static... yes"
 
-		if [ "$os" != "MINGW" ] && [ "$os" != "CYGWIN" ] && [ "$os" != "OSX" ] && [ "$os" != "DOS" ]; then
-			log 1 "WARNING: static is only known to work on Windows, DOS, and MacOSX"
+		if [ "$os" != "MINGW" ] && [ "$os" != "CYGWIN" ] && [ "$os" != "OSX" ]; then
+			log 1 "WARNING: static is only known to work on Windows, and MacOSX"
 			log 1 "WARNING: use static at your own risk on this platform"
 
 			sleep 5
@@ -644,7 +644,7 @@ check_params() {
 	fi
 
 	if [ "$enable_unicode" = "1" ]; then
-		if [ "$os" = "MINGW" ] || [ "$os" = "CYGWIN" ] || [ "$os" = "DOS" ]; then
+		if [ "$os" = "MINGW" ] || [ "$os" = "CYGWIN" ]; then
 			enable_unicode="2"
 		else
 			enable_unicode="0"
@@ -784,10 +784,7 @@ check_params() {
 		log 1 "checking console application... enabled"
 	fi
 
-	if [ "$enable_network" = "1" ] && [ "$os" = "DOS" ]; then
-		log 1 "checking network... DOS, skipping"
-		enable_network=0
-	elif [ "$enable_network" != "0" ]; then
+    if [ "$enable_network" != "0" ]; then
 		log 1 "checking network... found"
 	else
 		log 1 "checking network... disabled"
@@ -1023,10 +1020,6 @@ check_params() {
 		grfcodec=""
 	fi
 
-	if [ "$os" = "DOS" ]; then
-		with_threads="0"
-	fi
-
 	if [ "$os" != "OSX" ] && [ "$with_application_bundle" != "0" ]; then
 		if [ "$with_application_bundle" = "1" ]; then
 			with_application_bundle="0"
@@ -1129,7 +1122,7 @@ check_params() {
 	fi
 
 	if [ "$personal_dir" = "1" ]; then
-		if [ "$os" = "MINGW" ] || [ "$os" = "CYGWIN" ] || [ "$os" = "DOS" ] || [ "$os" = "HAIKU" ]; then
+		if [ "$os" = "MINGW" ] || [ "$os" = "CYGWIN" ] || [ "$os" = "HAIKU" ]; then
 			personal_dir="OpenTTD"
 		elif [ "$os" = "OSX" ]; then
 			personal_dir="Documents/OpenTTD"
@@ -1603,11 +1596,11 @@ make_cflags_and_ldflags() {
 		fi
 	fi
 
-	if [ "$os" != "CYGWIN" ] && [ "$os" != "HAIKU" ] && [ "$os" != "OPENBSD" ] && [ "$os" != "MINGW" ] && [ "$os" != "OSX" ] && [ "$os" != "DOS" ] && [ "$os" != "OS2" ]; then
+	if [ "$os" != "CYGWIN" ] && [ "$os" != "HAIKU" ] && [ "$os" != "OPENBSD" ] && [ "$os" != "MINGW" ] && [ "$os" != "OSX" ] && [ "$os" != "OS2" ]; then
 		LIBS="$LIBS -lpthread"
 	fi
 
-	if [ "$os" != "CYGWIN" ] && [ "$os" != "HAIKU" ] && [ "$os" != "MINGW" ] && [ "$os" != "DOS" ]; then
+	if [ "$os" != "CYGWIN" ] && [ "$os" != "HAIKU" ] && [ "$os" != "MINGW" ]; then
 		LIBS="$LIBS -lc"
 	fi
 
@@ -2328,7 +2321,7 @@ detect_awk() {
 
 detect_os() {
 	if [ "$os" = "DETECT" ]; then
-		# Detect UNIX, OSX, FREEBSD, DRAGONFLY, OPENBSD, NETBSD, HPUX, SUNOS, CYGWIN, MINGW, OS2, and DOS
+		# Detect UNIX, OSX, FREEBSD, DRAGONFLY, OPENBSD, NETBSD, HPUX, SUNOS, CYGWIN, MINGW, and OS2
 
 		# Try first via dumpmachine, then via uname
 		os=`echo "$host" | tr '[A-Z]' '[a-z]' | $awk '
@@ -2345,7 +2338,6 @@ detect_os() {
 					/cygwin/       { print "CYGWIN";    exit}
 					/mingw/        { print "MINGW";     exit}
 					/os2/          { print "OS2";       exit}
-					/dos/          { print "DOS";       exit}
 		'`
 
 		if [ -z "$os" ]; then
@@ -2369,7 +2361,7 @@ detect_os() {
 		if [ -z "$os" ]; then
 			log 1 "detecting OS... none detected"
 			log 1 "I couldn't detect your OS. Please use --os=OS to force one"
-			log 1 "Allowed values are: UNIX, OSX, FREEBSD, DRAGONFLY, OPENBSD, NETBSD, HPUX, HAIKU, SUNOS, CYGWIN, MINGW, OS2, and DOS"
+			log 1 "Allowed values are: UNIX, OSX, FREEBSD, DRAGONFLY, OPENBSD, NETBSD, HPUX, HAIKU, SUNOS, CYGWIN, MINGW, and OS2"
 			exit 1
 		fi
 
@@ -3453,7 +3445,7 @@ showhelp() {
 	echo "  --os=OS                        the OS we are compiling for [DETECT]"
 	echo "                                 DETECT/UNIX/OSX/FREEBSD/DRAGONFLY/OPENBSD/"
 	echo "                                 NETBSD/HPUX/SUNOS/CYGWIN/"
-	echo "                                 MINGW/OS2/DOS/HAIKU"
+	echo "                                 MINGW/OS2/HAIKU"
 	echo ""
 	echo "Paths:"
 	echo "  --prefix-dir=dir               specifies the prefix for all installed"