cmake: fix directory separators in generated packageConfig.cmake files

On windows, meson would mix posix and windows dir separators in the
computed PACKAGE_RELATIVE_PATH.

Here we force posix directory separator even on Windows. This matches
the CMake behavior and fixes interpretation of the resulting path.

Fixes #6955
Fixes #9702

3 files changed, 25 insertions, 0 deletions

diff --git a/test cases/cmake/26 cmake package prefix dir/cmakePackagePrefixDirConfig.cmake.in b/test cases/cmake/26 cmake package prefix dir/cmakePackagePrefixDirConfig.cmake.in
new file mode 100644
index 0000000..a18cb7d
--- /dev/null
+++ b/test cases/cmake/26 cmake package prefix dir/cmakePackagePrefixDirConfig.cmake.in
@@ -0,0 +1 @@
+@PACKAGE_INIT@
diff --git a/test cases/cmake/26 cmake package prefix dir/meson.build b/test cases/cmake/26 cmake package prefix dir/meson.build
new file mode 100644
index 0000000..851371b
--- /dev/null
+++ b/test cases/cmake/26 cmake package prefix dir/meson.build
@@ -0,0 +1,19 @@
+project('cmakePackagePrefixDir', 'c', version: '1.0.0')
+
+cmake = import('cmake')
+
+cmake.configure_package_config_file(
+    name: 'cmakePackagePrefixDir',
+    input: 'cmakePackagePrefixDirConfig.cmake.in',
+    configuration: configuration_data(),
+)
+
+# NOTE: can't use fs.read because cmakePackagePrefixDirConfig.cmake is in build_dir
+python = find_program('python3')
+lines = run_command(python, '-c',
+    '[print(line, end="") for line in open("@0@")]'.format(meson.current_build_dir() / 'cmakePackagePrefixDirConfig.cmake'), check : true,
+).stdout().split('\n')
+
+message(lines)
+
+assert(lines[5] == 'get_filename_component(PACKAGE_PREFIX_DIR "${CMAKE_CURRENT_LIST_DIR}/../../.." ABSOLUTE)')
diff --git a/test cases/cmake/26 cmake package prefix dir/test.json b/test cases/cmake/26 cmake package prefix dir/test.json
new file mode 100644
index 0000000..d6a9505
--- /dev/null
+++ b/test cases/cmake/26 cmake package prefix dir/test.json
@@ -0,0 +1,5 @@
+{
+  "installed": [
+    {"type": "file", "file": "usr/lib/cmake/cmakePackagePrefixDir/cmakePackagePrefixDirConfig.cmake"}
+  ]
+}