In file included from ../gnome-terminal-3.46.4/src/terminal-screen.cc:36:
/usr/include/sys/sysctl.h:499:2: error: unknown type name 'u_long'

XXX push upstream

Index: meson.build
--- meson.build.orig
+++ meson.build
@@ -163,7 +163,7 @@ config_h.set('ENABLE_SEARCH_PROVIDER', get_option('sea
 # Enable libc features
 
 libc_feature_defines = [
-  ['_GNU_SOURCE', '1'],
+  ['_BSD_SOURCE', '1'],
   ['_POSIX_C_SOURCE', '200809L'],
   ['_XOPEN_SOURCE', '700'],
   ['_XOPEN_SOURCE_EXTENDED', '1'],
@@ -229,7 +229,11 @@ assert(get_option('b_lto') == false, 'LTO not supporte
 
 # Check for functions
 
-libdl_dep = cxx.find_library('dl')
+if build_machine.system() == 'openbsd'
+  libdl_dep = []
+else
+  libdl_dep = cxx.find_library('dl')
+endif
 
 check_dl_functions_required = [
   'dlsym',