build-sys: work around broken linker when testing --version-script support

The linker on FreeBSD seems to be broken and fails for other reasons
when testing for support of the --version-script flag. The error
that is reported is:

local symbol 'environ' in /usr/lib/crt1.o is referenced by DSO.

Also __progname is needed.

To work around this problem we add a test.syms file that only has
these two symbols in it, which is enough for the test in
configure.ac and gives version script support in case of the
broken linker.

On FreeBSD TPM 1.2 related tests were failing due to test case 6
failures in case no linker script was used. (Very odd.) This patch
fixes this problem.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>

configure.ac

@@ -59,7 +59,7 @@ if test "$DEBUG" = "yes"; then
 fi
 AC_SUBST(DEBUG_DEFINES, $debug_defines)
 
-AX_CHECK_LINK_FLAG([-Wl,--version-script=$srcdir/src/libtpms.syms],
+AX_CHECK_LINK_FLAG([-Wl,--version-script=$srcdir/src/test.syms],
                    [have_version_script="yes"],
                    [have_version_script="no"])
 AM_CONDITIONAL([HAVE_VERSION_SCRIPT], [test "x$have_version_script" = "xyes"])

src/Makefile.am

@@ -588,6 +588,7 @@ check-local:
 EXTRA_DIST = \
 	tpm12/tpm_crypto_freebl.c \
 	tpm12/tpm_crypto.c \
-	libtpms.syms
+	libtpms.syms \
+	test.syms
 
 CLEANFILES = a.out

src/test.syms

@@ -0,0 +1,9 @@
+# Symbol file for the linker. For testing in configure.ac only
+TEST {
+    global:
+	# two work-around for a broken link
+	environ;
+	__progname;
+    local:
+	*;
+};