OPENGL: Resolve OpenGL functions on run-time.

Formerly we relied on static linkage. However, in the presense of modern
OpenGL (ES) implementations it is not easily identifable which library to link
against. For example, on Linux amd64 with nVidia drivers and SDL2 setup to
create a GLES 1.1 context one would need to link against libGL.so. However,
traditionally GLES 1.1 required to link against libGLESv1_CM.so. To prevent a
huge mess we simply resolve the OpenGL functions on run-time now and stop
linking against a static library (in most cases).

GLES support needs to be enabled manually on configure time for now.

Tizen changes have NOT been tested.

1 files changed, 16 insertions, 94 deletions

diff --git a/configure b/configure
index 0e7a5a9b56..8d465bc37c 100755
--- a/configure
+++ b/configure
@@ -134,7 +134,7 @@ _theoradec=auto
 _faad=auto
 _fluidsynth=auto
 _opengl=auto
-_opengles=auto
+_opengles=no
 _readline=auto
 _freetype2=auto
 _taskbar=auto
@@ -964,8 +964,8 @@ Optional Libraries:
   --with-mpeg2-prefix=DIR  Prefix where libmpeg2 is installed (optional)
   --enable-mpeg2           enable mpeg2 codec for cutscenes [autodetect]
 
-  --with-opengl-prefix=DIR Prefix where OpenGL (ES) is installed (optional)
   --disable-opengl         disable OpenGL (ES) support [autodetect]
+  --enable-opengles        enable forced OpenGL ES mode [disabled]
 
   --with-jpeg-prefix=DIR   Prefix where libjpeg is installed (optional)
   --disable-jpeg           disable JPEG decoder [autodetect]
@@ -1073,6 +1073,8 @@ for ac_option in $@; do
 	--disable-libunity)       _libunity=no    ;;
 	--enable-opengl)          _opengl=yes     ;;
 	--disable-opengl)         _opengl=no      ;;
+	--enable-opengles)        _opengles=yes   ;;
+	--disable-opengles)       _opengles=no    ;;
 	--enable-bink)            _bink=yes       ;;
 	--disable-bink)           _bink=no        ;;
 	--enable-verbose-build)   _verbose_build=yes ;;
@@ -1175,11 +1177,6 @@ for ac_option in $@; do
 		LIBUNITY_CFLAGS="-I$arg/include"
 		LIBUNITY_LIBS="-L$arg/lib"
 		;;
-	--with-opengl-prefix=*)
-		arg=`echo $ac_option | cut -d '=' -f 2`
-		OPENGL_CFLAGS="-I$arg/include"
-		OPENGL_LIBS="-L$arg/lib"
-		;;
 	--backend=*)
 		_backend=`echo $ac_option | cut -d '=' -f 2`
 		;;
@@ -2990,6 +2987,9 @@ if test -n "$_host"; then
 			_mt32emu=no
 			_timidity=no
 			_vkeybd=yes
+			# Tizen relies on the OpenGL ES output thus we always enable it.
+			_opengl=yes
+			_opengles=yes
 			;;
 		webos)
 			_backend="webos"
@@ -4154,101 +4154,23 @@ case $_backend in
 		if test "$_opengl" = yes ; then
 			_opengl=yes
 			_opengles=yes
-			OPENGL_LIBS="-lGLES_CM -lEGL -lX11"
-			OPENGL_CFLAGS="$OPENGL_LIBS"
-			append_var LIBS "$OPENGL_LIBS"
-			append_var INCLUDES "$OPENGL_CFLAGS"
+			append_var LIBS "-lGLES_CM -lEGL -lX11"
 		fi
 		;;
 esac
 
 if test "$_opengl" = auto ; then
-	_opengl=no
-	if test "$_backend" = "sdl" ; then
-		# Try different header filenames
-		# 1) GL/gl.h         This is usually used on POSIX and Windows systems
-		# 2) OpenGL/gl.h     This is used on Mac OS X
-		# 3) GLES/gl.h       This is used for OpenGL ES 1.x
-		for i in "GL/gl.h" "OpenGL/gl.h" "GLES/gl.h"; do
-			# Test the current header for OpenGL
-			cat > $TMPC << EOF
-#include <$i>
-#include <stdio.h>
-int main(void) { printf("ANTIVIRUS FALSE POSITIVE WORKAROUND"); return GL_VERSION_1_1; }
-EOF
-			cc_check $DEFINES $OPENGL_CFLAGS $OPENGL_LIBS && _opengl=yes && break
-
-			# Test the current header for OpenGL ES
-			cat > $TMPC << EOF
-#include <$i>
-int main(void) { return GL_OES_VERSION_1_1; }
-EOF
-			cc_check $DEFINES $OPENGL_CFLAGS $OPENGL_LIBS && _opengl=yes && _opengles=yes && break
-
-			# Test the current header for OpenGL ES on SBCs (Raspberry Pi, Cubieboard, etc)
-			cat > $TMPC << EOF
-#include <$i>
-int main(void) { return GL_VERSION_ES_CM_1_1; }
-EOF
-			cc_check $DEFINES $OPENGL_CFLAGS $OPENGL_LIBS && _opengl=yes && _opengles=yes && break
-		done
-	fi
-fi
-if test "$_opengl" = yes ; then
-	# Our simple test case
-	cat > $TMPC << EOF
-int main(void) { return 0; }
-EOF
-
-	_opengl=no
-	# Try different library names
-	if test "$_opengles" = "yes" ; then
-		# 1) GLES_CM    This is usually used for OpenGL ES 1.1 (Common profile)
-		# 2) GLESv1_CM  This is used by the Windows Mali OpenGL ES 1.1 Emulator
-		# 3) glesv1     This is used by the Linux Mali OpenGL ES 1.1 Emulator
-		_opengles=no
-		for lib in "-lGLES_CM" "-lGLESv1_CM" "-lglesv1"; do
-			if cc_check_no_clean $DEFINES $OPENGL_CFLAGS $OPENGL_LIBS $lib
-				then
-				_opengl=yes
-				_opengles=yes
-				OPENGL_LIBS="$OPENGL_LIBS $lib"
-				break
-			fi
-		done
-	else
-		# 1) -framework OpenGL  This is used on Mac OS X
-		# 2) GL                 This is usually used on POSIX systems
-		# 3) opengl32           This is used on Windows
-		#
-		# We try "-framework OpenGL" first here to assure it will always be
-		# picked up by the configure script on Mac OS X, even when a libGL
-		# exists.
-		for lib in "-framework OpenGL" "-lGL" "-lopengl32"; do
-			if cc_check_no_clean $DEFINES $OPENGL_CFLAGS $OPENGL_LIBS $lib
-				then
-				_opengl=yes
-				OPENGL_LIBS="$OPENGL_LIBS $lib"
-				break
-			fi
-		done
-	fi
-	cc_check_clean
+	case $_backend in
+		sdl)
+			_opengl=yes
+			;;
 
-	if test "$_opengl" = yes ; then
-		append_var LIBS "$OPENGL_LIBS"
-		append_var INCLUDES "$OPENGL_CFLAGS"
-	fi
+		*)
+			_opengl=no
+			;;
+	esac
 fi
 
-case $_host_os in
-	tizen)
-		# components live in non-standard locations so just assume sane SDK
-		_opengl=yes
-		_opengles=yes
-		;;
-esac
-
 if test "$_opengles" = "yes" ; then
 	echo "yes (OpenGL ES)"
 else