Pass awk detected by configure to regress tests.

Some platforms' basic awk don't have toupper, but other awks like nawk
or gawk do.  Pass the one found by configure through to the regress
tests, and make a wrapper for it so we don't need to modify any tests.

Makefile.in

@@ -806,6 +806,7 @@ TEST_SSH_SSHD="$(BUILDDIR)/sshd"
 
 interop-tests t-exec file-tests extra-tests: regress-prep regress-binaries $(TARGETS)
 	cd $(srcdir)/regress || exit $$?; \
+	AWK='@AWK@' \
 	EGREP='@EGREP@' \
 	OPENSSL_BIN='@OPENSSL_BIN@' \
 	$(MAKE) \

regress/test-exec.sh

@@ -79,6 +79,14 @@ if test "x${EGREP}" != "x"; then
 }
 fi
 
+# Likewise with awk.
+if test "x${AWK}" != "x"; then
+	awk ()
+{
+	${AWK} "$@"
+}
+fi
+
 SRC=`dirname ${SCRIPT}`
 
 # defaults