meson: fix logic for generating .pc files with old glvnd

We want to generate PC files for non-glvnd builds and for builds with
old glvnd, but the current logic doesn't do that, it builds them
unconditionally, and for GLES it builds the shared libraries, which is
also not what we want. This does not generate .pc files for gles1 or
gles2. Which it we weren't doing before either, making this not a
regression but a return to status-quo.o

Closes: https://gitlab.freedesktop.org/mesa/mesa/issues/1838
Fixes: 93df862b6a
       ("meson: re-add incorrect pkg-config files with GLVND for backward compatibility")
Reviewed-by: Matt Turner <mattst88@gmail.com>

meson.build

@@ -100,7 +100,7 @@ endif
 
 # shared-glapi is required if at least two OpenGL APIs are being built
 if not with_shared_glapi
-  if ((with_gles1 == 'true' and with_gles2 == 'true') or 
+  if ((with_gles1 == 'true' and with_gles2 == 'true') or
       (with_gles1 == 'true' and with_opengl) or
       (with_gles2 == 'true' and with_opengl))
     error('shared-glapi required for building two or more of OpenGL, OpenGL ES 1.x, OpenGL ES 2.x')
@@ -397,7 +397,7 @@ endif
 if with_glx != 'disabled'
   if not (with_platform_x11 and with_any_opengl)
     error('Cannot build GLX support without X11 platform support and at least one OpenGL API')
-  elif with_glx == 'gallium-xlib' 
+  elif with_glx == 'gallium-xlib'
     if not with_gallium
       error('Gallium-xlib based GLX requires at least one gallium driver')
     elif not with_gallium_softpipe
@@ -405,7 +405,7 @@ if with_glx != 'disabled'
     elif with_dri
       error('gallium-xlib conflicts with any dri driver')
     endif
-  elif with_glx == 'xlib' 
+  elif with_glx == 'xlib'
     if with_dri
       error('xlib conflicts with any dri driver')
     endif
@@ -1326,6 +1326,7 @@ else
 endif
 
 dep_glvnd = null_dep
+glvnd_missing_pc_files = false
 if with_glvnd
   dep_glvnd = dependency('libglvnd', version : '>= 0.2.0')
   # GLVND until commit 0dfaea2bcb7cdcc785f9 ("Add pkg-config files for EGL, GL,
@@ -1462,7 +1463,7 @@ if with_platform_x11
   if with_glx == 'dri' or with_glx == 'gallium-xlib'
     dep_glproto = dependency('glproto', version : '>= 1.4.14')
   endif
-  if with_glx == 'dri' 
+  if with_glx == 'dri'
     if with_dri_platform == 'drm'
       dep_dri2proto = dependency('dri2proto', version : '>= 2.8')
       dep_xxf86vm = dependency('xxf86vm')

src/egl/meson.build

@@ -176,21 +176,23 @@ libegl = shared_library(
 # If using glvnd the pkg-config header should not point to EGL_mesa, it should
 # point to EGL. glvnd is only available on unix like platforms so adding -l
 # should be safe here
-if with_glvnd and glvnd_missing_pc_files
-  _egl = '-L${libdir} -lEGL'
-else
-  _egl = libegl
-endif
+if not with_glvnd or glvnd_missing_pc_files
+  if glvnd_missing_pc_files
+    _egl = '-L${libdir} -lEGL'
+  else
+    _egl = libegl
+  endif
 
-pkg.generate(
-  name : 'egl',
-  description : 'Mesa EGL Library',
-  version : meson.project_version(),
-  libraries : _egl,
-  libraries_private: gl_priv_libs,
-  requires_private : gl_priv_reqs,
-  extra_cflags : gl_pkgconfig_c_flags,
-)
+  pkg.generate(
+    name : 'egl',
+    description : 'Mesa EGL Library',
+    version : meson.project_version(),
+    libraries : _egl,
+    libraries_private: gl_priv_libs,
+    requires_private : gl_priv_reqs,
+    extra_cflags : gl_pkgconfig_c_flags,
+  )
+endif
 
 if with_tests and prog_nm.found()
   if with_glvnd

src/mapi/meson.build

@@ -35,7 +35,7 @@ if with_shared_glapi
 else
   libglapi = []
 endif
-if not with_glvnd or glvnd_missing_pc_files
+if not with_glvnd
   if with_gles1
     subdir('es1api')
   endif

src/meson.build

@@ -111,12 +111,12 @@ endif
 
 # This must be after at least mesa, glx, and gallium, since libgl will be
 # defined in one of those subdirs depending on the glx provider.
-if with_glx != 'disabled'
+if with_glx != 'disabled' and (not with_glvnd or glvnd_missing_pc_files)
   # If using glvnd the pkg-config header should not point to GL_mesa, it should
   # point to GL. glvnd is only available on unix like platforms so adding -l
   # should be safe here
   # TODO: in the glvnd case glvnd itself should really be providing this.
-  if with_glvnd and glvnd_missing_pc_files
+  if glvnd_missing_pc_files
     _gl = '-L${libdir} -lGL'
   else
     _gl = libgl