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

@@ -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,

src/egl/meson.build

@@ -176,13 +176,14 @@ 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
+if not with_glvnd or glvnd_missing_pc_files
+  if glvnd_missing_pc_files
     _egl = '-L${libdir} -lEGL'
-else
+  else
     _egl = libegl
-endif
+  endif
 
-pkg.generate(
+  pkg.generate(
     name : 'egl',
     description : 'Mesa EGL Library',
     version : meson.project_version(),
@@ -190,7 +191,8 @@ pkg.generate(
     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