test: force Autoconf config.site to /dev/null.

From https://bugs.gnu.org/76622 (automake-patches).

* t/ax/test-defs.in: Set `CONFIG_SITE' to `/dev/null' to avoid
the local system's Autoconf site defaults from breaking the test
environment. Original report from Nelson Beebe, 26 Feb 2025.
* NEWS: mention this.

diff --git a/NEWS b/NEWS
index f46191a3c3903e9bcfdd68fb5dc17754a3a12bdd..62bfb36fdd23891c568c0cd8ba6bf3698e878f58 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -2,7 +2,7 @@ For planned incompatibilities in a possible future Automake 2.0 release,
 please see NEWS-future and start following the advice there now.
 
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-New in 1.17.90:
+New in 1.17.91:
 
 * New features added
 
@@ -38,16 +38,21 @@ New in 1.17.90:
     intended, i.e., omits the dependency on $(BUILT_SOURCES) for the
     distdir target. (bug#69908)
 
-  - The compile script is more robust to Windows configurations;
-    specifically, avoiding double-path translation on MSYS. (bug#75939)
-
   - Only warn about install.sh being found, instead of it being a fatal
     error. (bug#19964)
 
+  - The compile script is more robust to Windows configurations;
+    specifically, avoiding double-path translation on MSYS. (bug#75939)
+
+  - The test infrastructure sets the CONFIG_SITE environment variable to
+    /dev/null, to avoid the local system's Autoconf site defaults from
+    breaking the test environment. (bug#76622)
+    
   - AM_SILENT_RULES once again always ends with a newline. (bug#72267)
 
-  - AM_SANITY_CHECK outputs "no" on failure, so that a complete line is
-  printed to stdout before the error message is written to stderr. (bug#76448)
+  - AM_SANITY_CHECK now outputs "no" on failure, so that a complete line
+    is written to stdout before the error message is written to stderr.
+    (bug#76448)
 
 * Miscellaneous changes
 

diff --git a/t/ax/test-defs.in b/t/ax/test-defs.in
index 7554454948a26bb31e680f62c7d0b9b1cbf1fb80..9aed4ae10c4dc34071b2dcea3be83644bb58e3d3 100644 (file)
--- a/t/ax/test-defs.in
+++ b/t/ax/test-defs.in
@@ -22,6 +22,10 @@
 #   - Multiple inclusions of this file should be idempotent.
 #   - This code has to be 'set -e' clean.
 
+# Ensure a consistent test environment by ignoring the system's Autoconf
+# `configure` site defaults.
+CONFIG_SITE=/dev/null; export CONFIG_SITE
+
 # See whether the current test script is expected to use TAP or not.
 # Use a sensible default, while allowing the scripts to override this check.
 if test -z "$am_test_protocol"; then