Detect ASan in configure and disable incompatible tests.

ASan’s “interceptors” for crypt and crypt_r have a semantic conflict
with libxcrypt, requiring a few tests to be disabled for builds with
-fsanitize-address.  See commentary in test/crypt-badargs.c for an
explanation of the conflict, and commentary in build-aux/zw_detect_asan.m4
for why a configure test is required.

This does not work around https://github.com/google/sanitizers/issues/1365
which is an unrelated problem affecting test/special-char-salt.c and
which doesn’t currently break CI.

1 files changed, 12 insertions, 0 deletions

diff --git a/configure.ac b/configure.ac
index 0a933f7..f05b95f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -79,6 +79,18 @@ AC_CACHE_CHECK([whether the preprocessor ($CPP) supports -dD],
 ])
 AC_SUBST([HAVE_CPP_dD], [$ac_cv_prog_cpp_dD])
 
+# Some of the tests need to be conditionally compiled depending on
+# whether ASan is active.
+AC_CACHE_CHECK([whether we are compiling with ASan],
+  [ac_cv_c_address_sanitizer],
+  [zw_ASAN_IFELSE(
+    [ac_cv_c_address_sanitizer=yes],
+    [ac_cv_c_address_sanitizer=no])])
+if test x$ac_cv_c_address_sanitizer = xyes; then
+  AC_DEFINE([XCRYPT_USE_ASAN], [1],
+    [Define when compiling with ASan.  Only affects tests.])
+fi
+
 # Checks for libraries: currently none needed.
 
 # Checks for header files.