meson: Remove gles_headless_enabled

Use the `mesa_works` variable instead to simplify, the two variables
have the same value.

Signed-off-by: Barnabás Pőcze <barnabas.pocze@ideasonboard.com>
Reviewed-by: Milan Zamazal <mzamazal@redhat.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Bryan O'Donoghue <bod.linux@nxsw.ie>

src/libcamera/meson.build

@@ -74,12 +74,6 @@ mesa_works = cc.check_header('EGL/egl.h', required: false)
 libegl = dependency('egl', required : false)
 libglesv2 = dependency('glesv2', required : false)
 
-if mesa_works
-    gles_headless_enabled = true
-else
-    gles_headless_enabled = false
-endif
-
 subdir('base')
 subdir('converter')
 subdir('ipa')

src/libcamera/software_isp/meson.build

@@ -2,7 +2,7 @@
 
 softisp_enabled = pipelines.contains('simple')
 summary({'SoftISP support' : softisp_enabled}, section : 'Configuration')
-summary({'SoftISP GPU acceleration' : gles_headless_enabled}, section : 'Configuration')
+summary({'SoftISP GPU acceleration' : mesa_works}, section : 'Configuration')
 
 if not softisp_enabled
     subdir_done()
@@ -16,7 +16,7 @@ libcamera_internal_sources += files([
     'swstats_cpu.cpp',
 ])
 
-if gles_headless_enabled
+if mesa_works
     config_h.set('HAVE_DEBAYER_EGL', 1)
     libcamera_internal_sources += files([
         '../egl.cpp',