meson, egl: Support building for the Windows platform

Add a stub EGL driver for Windows
Fix compiler issues in egl/main
Ensure Windows build produces libEGL.dll
Default EGL to enabled for Windows when building a Gallium driver

Reviewed-by: Eric Engestrom <eric@engestrom.ch>
Reviewed By: Bill Kristiansen <billkris@microsoft.com>

Acked-by: Roland Scheidegger <sroland@vmware.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/12727>

meson.build

@@ -435,18 +435,19 @@ elif _egl == 'false'
 endif
 if _egl == 'auto'
   with_egl = (
-    not ['darwin', 'windows'].contains(host_machine.system()) and
-    with_dri and with_shared_glapi
+    host_machine.system() != 'darwin' and
+    (with_platform_windows or with_dri) and
+    with_shared_glapi
   )
 elif _egl == 'enabled'
-  if not with_dri and not with_platform_haiku
-    error('EGL requires dri')
+  if not with_dri and not with_platform_haiku and not with_platform_windows
+    error('EGL requires dri, haiku, or windows')
   elif not with_shared_glapi
     error('EGL requires shared-glapi')
   elif not ['disabled', 'dri'].contains(with_glx)
     error('EGL requires dri, but a GLX is being built without dri')
-  elif ['darwin', 'windows'].contains(host_machine.system())
-    error('EGL is not available on Windows or MacOS')
+  elif host_machine.system() == 'darwin'
+    error('EGL is not available on MacOS')
   endif
   with_egl = true
 else
@@ -913,6 +914,9 @@ endif
 if with_gbm and not with_platform_android
   pre_args += '-DHAVE_DRM_PLATFORM'
 endif
+if with_platform_windows
+  pre_args += '-DHAVE_WINDOWS_PLATFORM'
+endif
 
 with_android_stub = get_option('android-stub')
 if with_android_stub and not with_platform_android
@@ -2188,6 +2192,9 @@ if with_egl
   if with_dri3
     egl_drivers += 'builtin:egl_dri3'
   endif
+  if with_platform_windows
+    egl_drivers += 'builtin:wgl'
+  endif
   lines += 'EGL drivers:     ' + ' '.join(egl_drivers)
 endif
 if with_egl or with_any_vk

src/egl/drivers/wgl/egl_wgl.c

@@ -0,0 +1,27 @@
+/*
+ * Copyright © Microsoft Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <egldriver.h>
+
+struct _egl_driver _eglDriver;
+

src/egl/main/eglcurrent.c

@@ -33,6 +33,7 @@
 #include "c99_compat.h"
 #include "c11/threads.h"
 #include "util/u_thread.h"
+#include "util/u_string.h"
 
 #include "egllog.h"
 #include "eglcurrent.h"

src/egl/main/egldisplay.c

@@ -35,7 +35,11 @@
 #include <assert.h>
 #include <stdlib.h>
 #include <string.h>
+#ifdef _WIN32
+#include <io.h>
+#else
 #include <unistd.h>
+#endif
 #include <fcntl.h>
 #include "c11/threads.h"
 #include "util/macros.h"
@@ -77,6 +81,7 @@ static const struct {
    { _EGL_PLATFORM_HAIKU, "haiku" },
    { _EGL_PLATFORM_SURFACELESS, "surfaceless" },
    { _EGL_PLATFORM_DEVICE, "device" },
+   { _EGL_PLATFORM_WINDOWS, "windows" },
 };
 
 

src/egl/main/egldisplay.h

@@ -52,6 +52,7 @@ enum _egl_platform_type {
    _EGL_PLATFORM_HAIKU,
    _EGL_PLATFORM_SURFACELESS,
    _EGL_PLATFORM_DEVICE,
+   _EGL_PLATFORM_WINDOWS,
 
    _EGL_NUM_PLATFORMS,
    _EGL_INVALID_PLATFORM = -1

src/egl/main/eglglobals.c

@@ -39,6 +39,7 @@
 #include "egldisplay.h"
 
 #include "util/macros.h"
+#include "util/os_misc.h"
 
 #ifdef HAVE_MINCORE
 #include <unistd.h>
@@ -137,7 +138,8 @@ EGLBoolean
 _eglPointerIsDereferencable(void *p)
 {
    uintptr_t addr = (uintptr_t) p;
-   const long page_size = getpagesize();
+   uint64_t page_size = 0;
+   os_get_page_size(&page_size);
 #ifdef HAVE_MINCORE
    unsigned char valid = 0;
 

src/egl/main/egllog.c

@@ -39,7 +39,6 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <strings.h>
 #include "c11/threads.h"
 #include "util/macros.h"
 #include "util/u_string.h"

src/egl/meson.build

@@ -140,6 +140,11 @@ elif with_platform_haiku
   files_egl += files('drivers/haiku/egl_haiku.cpp')
   link_for_egl += libgl
   deps_for_egl += cpp.find_library('be')
+elif with_platform_windows
+  c_args_for_egl += [
+    '-DEGLAPI=', '-DPUBLIC='
+  ]
+  files_egl += files('drivers/wgl/egl_wgl.c')
 endif
 
 if cc.has_function('mincore')
@@ -149,9 +154,11 @@ endif
 if not with_glvnd
   egl_lib_name = 'EGL' + get_option('egl-lib-suffix')
   egl_lib_version = '1.0.0'
+  egl_lib_soversion = host_machine.system() == 'windows' ? '' : '1'
 else
   egl_lib_name = 'EGL_@0@'.format(glvnd_vendor_name)
   egl_lib_version = '0.0.0'
+  egl_lib_soversion = '0'
   deps_for_egl += dep_glvnd
   files_egl += [g_egldispatchstubs_h, g_egldispatchstubs_c]
   files_egl += files('main/eglglvnd.c', 'main/egldispatchstubs.c')
@@ -181,6 +188,8 @@ libegl = shared_library(
   dependencies : [deps_for_egl, dep_dl, dep_libdrm, dep_clock, dep_thread, idep_mesautil],
   install : true,
   version : egl_lib_version,
+  soversion : egl_lib_soversion,
+  name_prefix : 'lib', # even on windows
 )
 
 if not with_glvnd