Add EGL-based backend for wxGLCanvas

Among other things, this enables wxGLCanvas to be used natively on
Wayland.

Closes https://github.com/wxWidgets/wxWidgets/pull/2038

Closes #17702.

configure

@@ -953,6 +953,8 @@ CXXFLAGS_VISIBILITY
 CFLAGS_VISIBILITY
 MesaGL_LIBS
 MesaGL_CFLAGS
+EGL_LIBS
+EGL_CFLAGS
 GLU_LIBS
 GLU_CFLAGS
 GL_LIBS
@@ -1029,7 +1031,6 @@ infodir
 docdir
 oldincludedir
 includedir
-runstatedir
 localstatedir
 sharedstatedir
 sysconfdir
@@ -1398,6 +1399,8 @@ GL_CFLAGS
 GL_LIBS
 GLU_CFLAGS
 GLU_LIBS
+EGL_CFLAGS
+EGL_LIBS
 MesaGL_CFLAGS
 MesaGL_LIBS
 LIBSECRET_CFLAGS
@@ -1458,7 +1461,6 @@ datadir='${datarootdir}'
 sysconfdir='${prefix}/etc'
 sharedstatedir='${prefix}/com'
 localstatedir='${prefix}/var'
-runstatedir='${localstatedir}/run'
 includedir='${prefix}/include'
 oldincludedir='/usr/include'
 docdir='${datarootdir}/doc/${PACKAGE_TARNAME}'
@@ -1711,15 +1713,6 @@ do
   | -silent | --silent | --silen | --sile | --sil)
     silent=yes ;;
 
-  -runstatedir | --runstatedir | --runstatedi | --runstated \
-  | --runstate | --runstat | --runsta | --runst | --runs \
-  | --run | --ru | --r)
-    ac_prev=runstatedir ;;
-  -runstatedir=* | --runstatedir=* | --runstatedi=* | --runstated=* \
-  | --runstate=* | --runstat=* | --runsta=* | --runst=* | --runs=* \
-  | --run=* | --ru=* | --r=*)
-    runstatedir=$ac_optarg ;;
-
   -sbindir | --sbindir | --sbindi | --sbind | --sbin | --sbi | --sb)
     ac_prev=sbindir ;;
   -sbindir=* | --sbindir=* | --sbindi=* | --sbind=* | --sbin=* \
@@ -1857,7 +1850,7 @@ fi
 for ac_var in	exec_prefix prefix bindir sbindir libexecdir datarootdir \
 		datadir sysconfdir sharedstatedir localstatedir includedir \
 		oldincludedir docdir infodir htmldir dvidir pdfdir psdir \
-		libdir localedir mandir runstatedir
+		libdir localedir mandir
 do
   eval ac_val=\$$ac_var
   # Remove trailing slashes.
@@ -2010,7 +2003,6 @@ Fine tuning of the installation directories:
   --sysconfdir=DIR        read-only single-machine data [PREFIX/etc]
   --sharedstatedir=DIR    modifiable architecture-independent data [PREFIX/com]
   --localstatedir=DIR     modifiable single-machine data [PREFIX/var]
-  --runstatedir=DIR       modifiable per-process data [LOCALSTATEDIR/run]
   --libdir=DIR            object code libraries [EPREFIX/lib]
   --includedir=DIR        C header files [PREFIX/include]
   --oldincludedir=DIR     C header files for non-gcc [/usr/include]
@@ -2413,6 +2405,8 @@ Some influential environment variables:
   GL_LIBS     linker flags for GL, overriding pkg-config
   GLU_CFLAGS  C compiler flags for GLU, overriding pkg-config
   GLU_LIBS    linker flags for GLU, overriding pkg-config
+  EGL_CFLAGS  C compiler flags for EGL, overriding pkg-config
+  EGL_LIBS    linker flags for EGL, overriding pkg-config
   MesaGL_CFLAGS
               C compiler flags for MesaGL, overriding pkg-config
   MesaGL_LIBS linker flags for MesaGL, overriding pkg-config
@@ -28269,6 +28263,90 @@ fi
 
                         found_gl=1
                         OPENGL_LIBS="-lGL -lGLU"
+
+                        if test "$WXGTK3" = 1; then
+
+pkg_failed=no
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for EGL" >&5
+$as_echo_n "checking for EGL... " >&6; }
+
+if test -n "$PKG_CONFIG"; then
+    if test -n "$EGL_CFLAGS"; then
+        pkg_cv_EGL_CFLAGS="$EGL_CFLAGS"
+    else
+        if test -n "$PKG_CONFIG" && \
+    { { $as_echo "$as_me:${as_lineno-$LINENO}: \$PKG_CONFIG --exists --print-errors \"egl >= 1.5\""; } >&5
+  ($PKG_CONFIG --exists --print-errors "egl >= 1.5") 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; then
+  pkg_cv_EGL_CFLAGS=`$PKG_CONFIG --cflags "egl >= 1.5" 2>/dev/null`
+else
+  pkg_failed=yes
+fi
+    fi
+else
+	pkg_failed=untried
+fi
+if test -n "$PKG_CONFIG"; then
+    if test -n "$EGL_LIBS"; then
+        pkg_cv_EGL_LIBS="$EGL_LIBS"
+    else
+        if test -n "$PKG_CONFIG" && \
+    { { $as_echo "$as_me:${as_lineno-$LINENO}: \$PKG_CONFIG --exists --print-errors \"egl >= 1.5\""; } >&5
+  ($PKG_CONFIG --exists --print-errors "egl >= 1.5") 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; then
+  pkg_cv_EGL_LIBS=`$PKG_CONFIG --libs "egl >= 1.5" 2>/dev/null`
+else
+  pkg_failed=yes
+fi
+    fi
+else
+	pkg_failed=untried
+fi
+
+
+
+if test $pkg_failed = yes; then
+
+if $PKG_CONFIG --atleast-pkgconfig-version 0.20; then
+        _pkg_short_errors_supported=yes
+else
+        _pkg_short_errors_supported=no
+fi
+        if test $_pkg_short_errors_supported = yes; then
+	        EGL_PKG_ERRORS=`$PKG_CONFIG --short-errors --errors-to-stdout --print-errors "egl >= 1.5"`
+        else
+	        EGL_PKG_ERRORS=`$PKG_CONFIG --errors-to-stdout --print-errors "egl >= 1.5"`
+        fi
+	# Put the nasty error message in config.log where it belongs
+	echo "$EGL_PKG_ERRORS" >&5
+
+
+                                    { $as_echo "$as_me:${as_lineno-$LINENO}: EGL 1.5+ not available. Will use GLX." >&5
+$as_echo "$as_me: EGL 1.5+ not available. Will use GLX." >&6;}
+
+
+elif test $pkg_failed = untried; then
+
+                                    { $as_echo "$as_me:${as_lineno-$LINENO}: EGL 1.5+ not available. Will use GLX." >&5
+$as_echo "$as_me: EGL 1.5+ not available. Will use GLX." >&6;}
+
+
+else
+	EGL_CFLAGS=$pkg_cv_EGL_CFLAGS
+	EGL_LIBS=$pkg_cv_EGL_LIBS
+        { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+
+                                    OPENGL_LIBS="$OPENGL_LIBS $EGL_LIBS"
+                                    $as_echo "#define wxUSE_GLCANVAS_EGL 1" >>confdefs.h
+
+
+fi
+                        fi
                     fi
                 fi