libopenjp2: don't link with pthreads on Windows

OpenJPEG uses the Windows threading primitives directly, so linking with
-pthread is unnecessary.

Also stop defining both MUTEX_win32 and MUTEX_pthread on Windows.

releases.json

@@ -1472,6 +1472,7 @@
       "libopenjp2"
     ],
     "versions": [
+      "2.5.0-3",
       "2.5.0-2",
       "2.5.0-1",
       "2.3.1-9",

subprojects/packagefiles/libopenjp2/meson.build

@@ -26,7 +26,7 @@ openjpeg_version_subdir = 'openjpeg-@0@.@1@'.format(
 )
 
 m_dep = cc.find_library('m', required: false)
-thread_dep = dependency('threads')
+pthread_dep = dependency('threads', required: false)
 rt_dep = cc.find_library('rt', required: false)
 
 wxwidgets_dep = dependency('wxWidgets', required: get_option('build_viewer'))

subprojects/packagefiles/libopenjp2/src/lib/openjp2/meson.build

@@ -156,24 +156,19 @@ endif
 #################################################################################
 # threading configuration
 #################################################################################
-cmake_thread_prefer_pthread = 'TRUE'
 if not get_option('opj_use_thread')
   message('Use stub thread implementation')
   openjp2_c_args += '-DMUTEX_stub'
-endif
-
-if get_option('opj_use_thread') and host_system == 'windows'
-  # add_definitions('-DMUTEX_win32')
+  thread_dep = dependency('', required: false)
+elif host_system == 'windows'
   message('Use win32 thread implementation')
   openjp2_c_args += '-DMUTEX_win32'
-endif
-
-if get_option('opj_use_thread') and thread_dep.found()
+  thread_dep = dependency('', required: false)
+elif pthread_dep.found()
   message('Use pthread implementation')
   openjp2_c_args += '-DMUTEX_pthread'
-endif
-
-if get_option('opj_use_thread') and not thread_dep.found()
+  thread_dep = pthread_dep
+else
   error('FATAL_ERROR: No thread library found and thread/mutex support is required by "opj_use_thread" option')
 endif