fix transient failure on rust/12 bindgen

The test has a custom .h target that has the same name as the input in the
test's source directory.  Sometimes a compiler could build a target that
intends to use the file in the source tree, but finds an incomplete
output of the custom_target, causing the test to fail.

To fix this, move the generated headers in a subdirectory of the build
tree.

Signed-off-by: Paolo Bonzini <[email protected]>

Author: bonzini

test cases/rust/12 bindgen/dependencies/internal_dep.h

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: Apache-2.0
 // Copyright © 2022 Intel Corporation
 
-#include "gen.h"
+#include "gen/gen.h"
 
 int64_t add64(const int64_t, const int64_t);

test cases/rust/12 bindgen/src/gen_header.py renamed to test cases/rust/12 bindgen/gen/gen_header.py

@@ -0,0 +1,13 @@
+gen_h = custom_target(
+  'gen.h',
+  command : [find_program('gen_header.py'), '@INPUT@', '@OUTPUT@'],
+  output : 'gen.h',
+  input : meson.project_source_root() / 'src/header.h'
+)
+
+gen2_h = custom_target(
+  'other.h',
+  command : [find_program('gen_header.py'), '@INPUT@', '@OUTPUT@'],
+  output : 'other.h',
+  input : meson.project_source_root() / 'include/other.h'
+)

test cases/rust/12 bindgen/gen/meson.build

@@ -66,20 +66,7 @@ rust_bin = executable(
 test('main', rust_bin)
 
 # Test a generated header
-gen_h = custom_target(
-  'gen.h',
-  command : [find_program('src/gen_header.py'), '@INPUT@', '@OUTPUT@'],
-  output : 'gen.h',
-  input : 'src/header.h'
-)
-
-gen2_h = custom_target(
-  'other.h',
-  command : [find_program('src/gen_header.py'), '@INPUT@', '@OUTPUT@'],
-  output : 'other.h',
-  input : 'include/other.h'
-)
-
+subdir('gen')
 gen_rs = rust.bindgen(
   input : [gen_h, gen2_h],
   output : 'gen.rs',