--- a/tests/unilbrk/test-u8-possible-linebreaks.c
+++ b/tests/unilbrk/test-u8-possible-linebreaks.c
@@ -18,6 +18,19 @@
 
 #include <config.h>
 
+#ifdef IN_LIBUNISTRING_GNULIB_TESTS
+# include <stddef.h>
+# include "unitypes.h"
+# undef u8_possible_linebreaks
+extern void u8_possible_linebreaks (const uint8_t *, size_t, const char *, char *);
+static void
+u8_possible_linebreaks_v1 (const uint8_t *s, size_t n,
+                           const char *encoding, char *p)
+{
+  u8_possible_linebreaks (s, n, encoding, p);
+}
+#endif
+
 #include "unilbrk.h"
 
 #include <stdlib.h>
@@ -230,8 +243,7 @@
 {
   test_function (u8_possible_linebreaks, 2);
 #ifdef IN_LIBUNISTRING_GNULIB_TESTS
-# undef u8_possible_linebreaks
-  test_function (u8_possible_linebreaks, 1);
+  test_function (u8_possible_linebreaks_v1, 1);
 #endif
 
   return test_exit_status;
--- a/tests/unilbrk/test-u8-width-linebreaks.c
+++ b/tests/unilbrk/test-u8-width-linebreaks.c
@@ -18,6 +18,22 @@
 
 #include <config.h>
 
+#ifdef IN_LIBUNISTRING_GNULIB_TESTS
+# include <stddef.h>
+# include "unitypes.h"
+# undef u8_width_linebreaks
+extern int u8_width_linebreaks (const uint8_t *, size_t, int, int, int,
+                                const char *, const char *, char *);
+static int
+u8_width_linebreaks_v1 (const uint8_t *s, size_t n,
+                        int width, int start_column, int at_end_columns,
+                        const char *o, const char *encoding, char *p)
+{
+  return u8_width_linebreaks (s, n, width, start_column, at_end_columns,
+                              o, encoding, p);
+}
+#endif
+
 #include "unilbrk.h"
 
 #include <stdlib.h>
@@ -69,8 +85,7 @@
 {
   test_function (u8_width_linebreaks, 2);
 #ifdef IN_LIBUNISTRING_GNULIB_TESTS
-# undef u8_width_linebreaks
-  test_function (u8_width_linebreaks, 1);
+  test_function (u8_width_linebreaks_v1, 1);
 #endif
 
   return test_exit_status;
--- a/tests/unilbrk/test-u16-possible-linebreaks.c
+++ b/tests/unilbrk/test-u16-possible-linebreaks.c
@@ -18,6 +18,19 @@
 
 #include <config.h>
 
+#ifdef IN_LIBUNISTRING_GNULIB_TESTS
+# include <stddef.h>
+# include "unitypes.h"
+# undef u16_possible_linebreaks
+extern void u16_possible_linebreaks (const uint16_t *, size_t, const char *, char *);
+static void
+u16_possible_linebreaks_v1 (const uint16_t *s, size_t n,
+                            const char *encoding, char *p)
+{
+  u16_possible_linebreaks (s, n, encoding, p);
+}
+#endif
+
 #include "unilbrk.h"
 
 #include <stdlib.h>
@@ -245,8 +258,7 @@
 {
   test_function (u16_possible_linebreaks, 2);
 #ifdef IN_LIBUNISTRING_GNULIB_TESTS
-# undef u16_possible_linebreaks
-  test_function (u16_possible_linebreaks, 1);
+  test_function (u16_possible_linebreaks_v1, 1);
 #endif
 
   return test_exit_status;
--- a/tests/unilbrk/test-u16-width-linebreaks.c
+++ b/tests/unilbrk/test-u16-width-linebreaks.c
@@ -18,6 +18,22 @@
 
 #include <config.h>
 
+#ifdef IN_LIBUNISTRING_GNULIB_TESTS
+# include <stddef.h>
+# include "unitypes.h"
+# undef u16_width_linebreaks
+extern int u16_width_linebreaks (const uint16_t *, size_t, int, int, int,
+                                 const char *, const char *, char *);
+static int
+u16_width_linebreaks_v1 (const uint16_t *s, size_t n,
+                         int width, int start_column, int at_end_columns,
+                         const char *o, const char *encoding, char *p)
+{
+  return u16_width_linebreaks (s, n, width, start_column, at_end_columns,
+                               o, encoding, p);
+}
+#endif
+
 #include "unilbrk.h"
 
 #include <stdlib.h>
@@ -75,8 +91,7 @@
 {
   test_function (u16_width_linebreaks, 2);
 #ifdef IN_LIBUNISTRING_GNULIB_TESTS
-# undef u16_width_linebreaks
-  test_function (u16_width_linebreaks, 1);
+  test_function (u16_width_linebreaks_v1, 1);
 #endif
 
   return test_exit_status;
--- a/tests/unilbrk/test-u32-possible-linebreaks.c
+++ b/tests/unilbrk/test-u32-possible-linebreaks.c
@@ -18,6 +18,19 @@
 
 #include <config.h>
 
+#ifdef IN_LIBUNISTRING_GNULIB_TESTS
+# include <stddef.h>
+# include "unitypes.h"
+# undef u32_possible_linebreaks
+extern void u32_possible_linebreaks (const uint32_t *, size_t, const char *, char *);
+static void
+u32_possible_linebreaks_v1 (const uint32_t *s, size_t n,
+                            const char *encoding, char *p)
+{
+  u32_possible_linebreaks (s, n, encoding, p);
+}
+#endif
+
 #include "unilbrk.h"
 
 #include <stdlib.h>
@@ -245,8 +258,7 @@
 {
   test_function (u32_possible_linebreaks, 2);
 #ifdef IN_LIBUNISTRING_GNULIB_TESTS
-# undef u32_possible_linebreaks
-  test_function (u32_possible_linebreaks, 1);
+  test_function (u32_possible_linebreaks_v1, 1);
 #endif
 
   return test_exit_status;
--- a/tests/unilbrk/test-u32-width-linebreaks.c
+++ b/tests/unilbrk/test-u32-width-linebreaks.c
@@ -18,6 +18,22 @@
 
 #include <config.h>
 
+#ifdef IN_LIBUNISTRING_GNULIB_TESTS
+# include <stddef.h>
+# include "unitypes.h"
+# undef u32_width_linebreaks
+extern int u32_width_linebreaks (const uint32_t *, size_t, int, int, int,
+                                 const char *, const char *, char *);
+static int
+u32_width_linebreaks_v1 (const uint32_t *s, size_t n,
+                         int width, int start_column, int at_end_columns,
+                         const char *o, const char *encoding, char *p)
+{
+  return u32_width_linebreaks (s, n, width, start_column, at_end_columns,
+                               o, encoding, p);
+}
+#endif
+
 #include "unilbrk.h"
 
 #include <stdlib.h>
@@ -75,8 +91,7 @@
 {
   test_function (u32_width_linebreaks, 2);
 #ifdef IN_LIBUNISTRING_GNULIB_TESTS
-# undef u32_width_linebreaks
-  test_function (u32_width_linebreaks, 1);
+  test_function (u32_width_linebreaks_v1, 1);
 #endif
 
   return test_exit_status;
--- a/tests/unilbrk/test-ulc-possible-linebreaks.c
+++ b/tests/unilbrk/test-ulc-possible-linebreaks.c
@@ -18,6 +18,18 @@
 
 #include <config.h>
 
+#ifdef IN_LIBUNISTRING_GNULIB_TESTS
+# include <stddef.h>
+# undef ulc_possible_linebreaks
+extern void ulc_possible_linebreaks (const char *, size_t, const char *, char *);
+static void
+ulc_possible_linebreaks_v1 (const char *s, size_t n,
+                            const char *encoding, char *p)
+{
+  ulc_possible_linebreaks (s, n, encoding, p);
+}
+#endif
+
 #include "unilbrk.h"
 
 #include <stdlib.h>
@@ -71,8 +83,7 @@
 {
   test_function (ulc_possible_linebreaks, 2);
 #ifdef IN_LIBUNISTRING_GNULIB_TESTS
-# undef ulc_possible_linebreaks
-  test_function (ulc_possible_linebreaks, 1);
+  test_function (ulc_possible_linebreaks_v1, 1);
 #endif
 
   return test_exit_status;
--- a/tests/unilbrk/test-ulc-width-linebreaks.c
+++ b/tests/unilbrk/test-ulc-width-linebreaks.c
@@ -18,6 +18,21 @@
 
 #include <config.h>
 
+#ifdef IN_LIBUNISTRING_GNULIB_TESTS
+# include <stddef.h>
+# undef ulc_width_linebreaks
+extern int ulc_width_linebreaks (const char *, size_t, int, int, int,
+                                 const char *, const char *, char *);
+static int
+ulc_width_linebreaks_v1 (const char *s, size_t n,
+                         int width, int start_column, int at_end_columns,
+                         const char *o, const char *encoding, char *p)
+{
+  return ulc_width_linebreaks (s, n, width, start_column, at_end_columns,
+                               o, encoding, p);
+}
+#endif
+
 #include "unilbrk.h"
 
 #include <stdlib.h>
@@ -55,8 +70,7 @@
 {
   test_function (ulc_width_linebreaks, 2);
 #ifdef IN_LIBUNISTRING_GNULIB_TESTS
-# undef ulc_width_linebreaks
-  test_function (ulc_width_linebreaks, 1);
+  test_function (ulc_width_linebreaks_v1, 1);
 #endif
 
   return test_exit_status;