Allow using Python3 to run gen_dispatch.py

This way, we don't have to depend on Python2 on newer OSes.

configure.ac

@@ -41,7 +41,7 @@ m4_ifndef([XORG_MACROS_VERSION],
 XORG_MACROS_VERSION(1.8)
 XORG_DEFAULT_OPTIONS
 
-AC_CHECK_PROGS([PYTHON], [python2 python])
+AC_CHECK_PROGS([PYTHON], [python3 python2 python])
 
 # Initialize libtool
 AC_DISABLE_STATIC

meson.build

@@ -203,7 +203,10 @@ configure_file(input: 'epoxy.pc.in',
                install_dir: join_paths(epoxy_libdir, 'pkgconfig'))
 
 # Python
-python = find_program('python', required: true)
+python = find_program('python3', required: false)
+if not python.found()
+  python = find_program('python', required: true)
+endif
 
 # Generates the dispatch tables
 gen_dispatch_py = join_paths(meson.source_root(), 'src/gen_dispatch.py')