meson: refuse when prefix is not a child of rootprefix

This is most likely to happen when setting one but not the other.

Note that we already warn when rootprefixdir != rootprefix_default,
at the very end.

diff --git a/meson.build b/meson.build
index dc7cbc1c3ac817801c9ca80cbfcea48791b9dfcd..2c5150bfc18de93202af055d835c8f30336ad45c 100644 (file)
--- a/meson.build
+++ b/meson.build
@@ -115,6 +115,11 @@ prefixdir = get_option('prefix')
 if not prefixdir.startswith('/')
         error('Prefix is not absolute: "@0@"'.format(prefixdir))
 endif
+if prefixdir != rootprefixdir and not prefixdir.startswith(rootprefixdir.strip('/') + '/')
+        error('Prefix is not below root prefix (now rootprefix=@0@ prefix=@1@)'.format(
+                rootprefixdir, prefixdir))
+endif
+
 bindir = join_paths(prefixdir, get_option('bindir'))
 libdir = join_paths(prefixdir, get_option('libdir'))
 sysconfdir = join_paths(prefixdir, get_option('sysconfdir'))