Make function mbedtls_ssl_set_hostname(...) as optional

Now function mbedtls_ssl_set_hostname is compile-time configurable
in config.h with define MBEDTLS_X509_REMOVE_HOSTNAME_VERIFICATION.
This affects to many x509 API's. See config.h for details.
diff --git a/tests/scripts/all.sh b/tests/scripts/all.sh
index fe46b28..dac2e26 100755
--- a/tests/scripts/all.sh
+++ b/tests/scripts/all.sh
@@ -1280,6 +1280,20 @@
     if_build_succeeded tests/ssl-opt.sh
 }
 
+component_test_no_hostname_verification () {
+    msg "build: full + MBEDTLS_X509_REMOVE_HOSTNAME_VERIFICATION" # ~ 10s
+    scripts/config.pl full
+    scripts/config.pl unset MBEDTLS_MEMORY_BACKTRACE # too slow for tests
+    scripts/config.pl set MBEDTLS_X509_REMOVE_HOSTNAME_VERIFICATION
+    make CFLAGS='-Werror -O1'
+
+    msg "test: full + MBEDTLS_X509_REMOVE_HOSTNAME_VERIFICATION" # ~ 10s
+    make test
+
+    msg "test: ssl-opt.sh, full + MBEDTLS_X509_REMOVE_HOSTNAME_VERIFICATION" # ~ 1 min
+    if_build_succeeded tests/ssl-opt.sh
+}
+
 component_build_arm_none_eabi_gcc () {
     msg "build: arm-none-eabi-gcc, make" # ~ 10s
     scripts/config.pl baremetal