[PATCH 2/2] configure: Check that provided paths are absolute

[Michal Suchanek <msuchanek@suse.de>]

configure checks that its built-in directory options get an absolute
path. Copy the check for custom options.

Signed-off-by: Michal Suchanek <msuchanek@suse.de>
---
v6: new patch
---
 configure.ac | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/configure.ac b/configure.ac
index d6da5ee9ae9a..de01e08cf2e8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -97,6 +97,23 @@ AC_ARG_WITH([module_directory],
         [], [with_module_directory=/lib/modules])
 AC_SUBST([module_directory], [$with_module_directory])
 
+# Check all directory arguments for consistency.
+for ac_var in	distconfdir rootlibdir module_directory
+do
+  eval ac_val=\$$ac_var
+  # Remove trailing slashes.
+  case $ac_val in
+    */ )
+      ac_val=`expr "X$ac_val" : 'X\(.*@<:@^/@:>@\)' \| "X$ac_val" : 'X\(.*\)'`
+      eval $ac_var=\$ac_val;;
+  esac
+  # Be sure to have absolute directory names.
+  case $ac_val in
+    @<:@\\/$@:>@* | ?:@<:@\\/@:>@* )  continue;;
+  esac
+  as_fn_error $? "expected an absolute directory name for --$ac_var: $ac_val"
+done
+
 AC_ARG_WITH([zstd],
 	AS_HELP_STRING([--with-zstd], [handle Zstandard-compressed modules @<:@default=disabled@:>@]),
 	[], [with_zstd=no])
-- 
2.42.0