Add test for configure_file in custom target command list

This was not tested at all earlier

test cases/common/76 configure file in custom target/src/meson.build

@@ -2,3 +2,19 @@ custom_target('thing',
 output : 'final.dat',
 input : cfile,
 command : [find_program('mycompiler.py'), '@INPUT@', '@OUTPUT@'])
+
+# Test usage of a `configure_file` as part of the command list
+py3 = find_program('python3', required : false)
+if not py3.found()
+  # Maybe 'python' is Python 3
+  py3 = find_program('python')
+endif
+
+compiler = configure_file(input : 'mycompiler.py',
+  output : 'mycompiler2.py',
+  configuration : configuration_data())
+
+custom_target('thing2',
+output : 'final2.dat',
+input : cfile,
+command : [py3, compiler, '@INPUT@', '@OUTPUT@'])