pkgconfig: Do not escape custom variables

We need to escape space in variables that gets into cflags or libs
because otherwise we cannot split compiler args when paths contains
spaces. But custom variables are unlikely to be path that gets used in
cflags/libs, and escaping them cause regression in GStreamer that use
space as separator in a list variable.

1 files changed, 23 insertions, 0 deletions

diff --git a/docs/markdown/snippets/pkgconfig_var_escaping.md b/docs/markdown/snippets/pkgconfig_var_escaping.md
new file mode 100644
index 0000000..de0ee96
--- /dev/null
+++ b/docs/markdown/snippets/pkgconfig_var_escaping.md
@@ -0,0 +1,23 @@
+## Unescaped variables in pkgconfig files
+
+Spaces in variable values are escaped with `\`, this is required in the case the
+value is a path that and is used in `cflags` or `libs` arguments. This was an
+undocumented behaviour that caused issues in the case the variable is a space
+separated list of items.
+
+For backward compatibility reasons this behaviour could not be changed, new
+keyword arguments have thus been added: `unescaped_variables` and
+`unescaped_uninstalled_variables`.
+
+```meson
+pkg = import('pkgconfig')
+...
+pkg.generate(lib,
+  variables: {
+    'mypath': '/path/with spaces/are/escaped',
+  },
+  unescaped_variables: {
+    'mylist': 'Hello World Is Not Escaped',
+  },
+)
+```