[Unit-tests] Add --enable-fake-dlclose configure flag so modules are not unloaded and ASAN could give more info and not just <unknown module>.

configure.ac

@@ -1986,6 +1986,16 @@ if test "${enable_address_sanitizer}" = "yes"; then
   APR_ADDTO(LDFLAGS, -fsanitize=address)
 fi
 
+#  Enable fake dlclose
+AC_ARG_ENABLE(fake_dlclose,
+  [AC_HELP_STRING([--enable-fake-dlclose],[Do not unload dynamic libraries])],
+  [enable_fake_dlclose="$enable_fake_dlclose"],
+  [enable_fake_dlclose="no"])
+
+if test "${enable_fake_dlclose}" = "yes"; then
+  APR_ADDTO(SWITCH_AM_CFLAGS, -DHAVE_FAKE_DLCLOSE)
+fi
+
 AC_ARG_ENABLE(,
   [AC_HELP_STRING([--enable-pool-sanitizer],[build with sanitizer friendly pool behavior])],
   [enable_pool_sanitizer="$enable_pool_sanitizer"],

src/switch_dso.c

@@ -91,7 +91,9 @@ SWITCH_DECLARE(void *) switch_dso_data_sym(switch_dso_lib_t lib, const char *sym
 void switch_dso_destroy(switch_dso_lib_t *lib)
 {
 	if (lib && *lib) {
+#ifndef HAVE_FAKE_DLCLOSE
 		dlclose(*lib);
+#endif
 		*lib = NULL;
 	}
 }