diff --git a/ChangeLog b/ChangeLog
index 3aa2250dd..7903fc741 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -2,6 +2,9 @@ mbed TLS ChangeLog (Sorted per branch, date)
 
 = mbed TLS 1.3.22 branch released 2017-xx-xx
 
+Features
+   * Allow comments in test data files.
+
 Bugfix
    * Fix memory leak in ssl_set_hostname() when called multiple times.
      Found by projectgus and jethrogb, #836.
@@ -45,9 +48,7 @@ Changes
    * Extend cert_write example program by options to set the CRT version
      and the message digest. Further, allow enabling/disabling of authority
      identifier, subject identifier and basic constraints extensions.
-
-Features
-   * Allow comments in test data files.
+   * Improve makefiles on Windows: don't run find, and call perl explicitly.
 
 = mbed TLS 1.3.21 branch released 2017-08-10
 
diff --git a/Makefile b/Makefile
index 441d1f9f2..def9c9a4a 100644
--- a/Makefile
+++ b/Makefile
@@ -55,11 +55,14 @@ clean:
 	$(MAKE) -C library clean
 	$(MAKE) -C programs clean
 	$(MAKE) -C tests clean
-	find . \( -name \*.gcno -o -name \*.gcda -o -name *.info \) -exec rm {} +
+ifndef WINDOWS
+	find . \( -name \*.gcno -o -name \*.gcda -o -name \*.info \) -exec rm {} +
+endif
 
 check: tests
 	$(MAKE) -C tests check
 
+ifndef WINDOWS
 test-ref-configs:
 	tests/scripts/test-ref-configs.pl
 
@@ -90,3 +93,4 @@ apidoc_clean:
 	then				    	\
 		rm -rf apidoc ;			\
 	fi
+endif
diff --git a/tests/Makefile b/tests/Makefile
index 307b7e13c..c4ee35d31 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -10,6 +10,8 @@ LOCAL_CFLAGS = $(WARNING_CFLAGS) -I../include -D_FILE_OFFSET_BITS=64
 LOCAL_LDFLAGS = -L../library -lmbedtls$(SHARED_SUFFIX)
 DLEXT=so
 
+PERL ?= perl
+
 ifndef SHARED
 DEP=../library/libmbedtls.a
 CHECK_PRELOAD=
@@ -89,103 +91,103 @@ all: $(APPS)
 
 test_suite_aes.ecb.c : suites/test_suite_aes.function suites/test_suite_aes.ecb.data scripts/generate_code.pl suites/helpers.function suites/main_test.function
 	echo   "  Generate	$@"
-	scripts/generate_code.pl suites test_suite_aes test_suite_aes.ecb
+	$(PERL) scripts/generate_code.pl suites test_suite_aes test_suite_aes.ecb
 
 test_suite_aes.cbc.c : suites/test_suite_aes.function suites/test_suite_aes.cbc.data scripts/generate_code.pl suites/helpers.function suites/main_test.function
 	echo   "  Generate	$@"
-	scripts/generate_code.pl suites test_suite_aes test_suite_aes.cbc
+	$(PERL) scripts/generate_code.pl suites test_suite_aes test_suite_aes.cbc
 
 test_suite_aes.cfb.c : suites/test_suite_aes.function suites/test_suite_aes.cfb.data scripts/generate_code.pl suites/helpers.function suites/main_test.function
 	echo   "  Generate	$@"
-	scripts/generate_code.pl suites test_suite_aes test_suite_aes.cfb
+	$(PERL) scripts/generate_code.pl suites test_suite_aes test_suite_aes.cfb
 
 test_suite_aes.rest.c : suites/test_suite_aes.function suites/test_suite_aes.rest.data scripts/generate_code.pl suites/helpers.function suites/main_test.function
 	echo   "  Generate	$@"
-	scripts/generate_code.pl suites test_suite_aes test_suite_aes.rest
+	$(PERL) scripts/generate_code.pl suites test_suite_aes test_suite_aes.rest
 
 test_suite_cipher.aes.c : suites/test_suite_cipher.function suites/test_suite_cipher.aes.data scripts/generate_code.pl suites/helpers.function suites/main_test.function
 	echo   "  Generate	$@"
-	scripts/generate_code.pl suites test_suite_cipher test_suite_cipher.aes
+	$(PERL) scripts/generate_code.pl suites test_suite_cipher test_suite_cipher.aes
 
 test_suite_cipher.arc4.c : suites/test_suite_cipher.function suites/test_suite_cipher.arc4.data scripts/generate_code.pl suites/helpers.function suites/main_test.function
 	echo   "  Generate	$@"
-	scripts/generate_code.pl suites test_suite_cipher test_suite_cipher.arc4
+	$(PERL) scripts/generate_code.pl suites test_suite_cipher test_suite_cipher.arc4
 
 test_suite_cipher.ccm.c : suites/test_suite_cipher.function suites/test_suite_cipher.ccm.data scripts/generate_code.pl suites/helpers.function suites/main_test.function
 	echo   "  Generate	$@"
-	scripts/generate_code.pl suites test_suite_cipher test_suite_cipher.ccm
+	$(PERL) scripts/generate_code.pl suites test_suite_cipher test_suite_cipher.ccm
 
 test_suite_cipher.gcm.c : suites/test_suite_cipher.function suites/test_suite_cipher.gcm.data scripts/generate_code.pl suites/helpers.function suites/main_test.function
 	echo   "  Generate	$@"
-	scripts/generate_code.pl suites test_suite_cipher test_suite_cipher.gcm
+	$(PERL) scripts/generate_code.pl suites test_suite_cipher test_suite_cipher.gcm
 
 test_suite_cipher.blowfish.c : suites/test_suite_cipher.function suites/test_suite_cipher.blowfish.data scripts/generate_code.pl suites/helpers.function suites/main_test.function
 	echo   "  Generate	$@"
-	scripts/generate_code.pl suites test_suite_cipher test_suite_cipher.blowfish
+	$(PERL) scripts/generate_code.pl suites test_suite_cipher test_suite_cipher.blowfish
 
 test_suite_cipher.camellia.c : suites/test_suite_cipher.function suites/test_suite_cipher.camellia.data scripts/generate_code.pl suites/helpers.function suites/main_test.function
 	echo   "  Generate	$@"
-	scripts/generate_code.pl suites test_suite_cipher test_suite_cipher.camellia
+	$(PERL) scripts/generate_code.pl suites test_suite_cipher test_suite_cipher.camellia
 
 test_suite_cipher.des.c : suites/test_suite_cipher.function suites/test_suite_cipher.des.data scripts/generate_code.pl suites/helpers.function suites/main_test.function
 	echo   "  Generate	$@"
-	scripts/generate_code.pl suites test_suite_cipher test_suite_cipher.des
+	$(PERL) scripts/generate_code.pl suites test_suite_cipher test_suite_cipher.des
 
 test_suite_cipher.null.c : suites/test_suite_cipher.function suites/test_suite_cipher.null.data scripts/generate_code.pl suites/helpers.function suites/main_test.function
 	echo   "  Generate	$@"
-	scripts/generate_code.pl suites test_suite_cipher test_suite_cipher.null
+	$(PERL) scripts/generate_code.pl suites test_suite_cipher test_suite_cipher.null
 
 test_suite_cipher.padding.c : suites/test_suite_cipher.function suites/test_suite_cipher.padding.data scripts/generate_code.pl suites/helpers.function suites/main_test.function
 	echo   "  Generate	$@"
-	scripts/generate_code.pl suites test_suite_cipher test_suite_cipher.padding
+	$(PERL) scripts/generate_code.pl suites test_suite_cipher test_suite_cipher.padding
 
 test_suite_gcm.aes128_de.c : suites/test_suite_gcm.function suites/test_suite_gcm.aes128_de.data scripts/generate_code.pl suites/helpers.function suites/main_test.function
 	echo   "  Generate	$@"
-	scripts/generate_code.pl suites test_suite_gcm test_suite_gcm.aes128_de
+	$(PERL) scripts/generate_code.pl suites test_suite_gcm test_suite_gcm.aes128_de
 
 test_suite_gcm.aes192_de.c : suites/test_suite_gcm.function suites/test_suite_gcm.aes192_de.data scripts/generate_code.pl suites/helpers.function suites/main_test.function
 	echo   "  Generate	$@"
-	scripts/generate_code.pl suites test_suite_gcm test_suite_gcm.aes192_de
+	$(PERL) scripts/generate_code.pl suites test_suite_gcm test_suite_gcm.aes192_de
 
 test_suite_gcm.aes256_de.c : suites/test_suite_gcm.function suites/test_suite_gcm.aes256_de.data scripts/generate_code.pl suites/helpers.function suites/main_test.function
 	echo   "  Generate	$@"
-	scripts/generate_code.pl suites test_suite_gcm test_suite_gcm.aes256_de
+	$(PERL) scripts/generate_code.pl suites test_suite_gcm test_suite_gcm.aes256_de
 
 test_suite_gcm.aes128_en.c : suites/test_suite_gcm.function suites/test_suite_gcm.aes128_en.data scripts/generate_code.pl suites/helpers.function suites/main_test.function
 	echo   "  Generate	$@"
-	scripts/generate_code.pl suites test_suite_gcm test_suite_gcm.aes128_en
+	$(PERL) scripts/generate_code.pl suites test_suite_gcm test_suite_gcm.aes128_en
 
 test_suite_gcm.aes192_en.c : suites/test_suite_gcm.function suites/test_suite_gcm.aes192_en.data scripts/generate_code.pl suites/helpers.function suites/main_test.function
 	echo   "  Generate	$@"
-	scripts/generate_code.pl suites test_suite_gcm test_suite_gcm.aes192_en
+	$(PERL) scripts/generate_code.pl suites test_suite_gcm test_suite_gcm.aes192_en
 
 test_suite_gcm.aes256_en.c : suites/test_suite_gcm.function suites/test_suite_gcm.aes256_en.data scripts/generate_code.pl suites/helpers.function suites/main_test.function
 	echo   "  Generate	$@"
-	scripts/generate_code.pl suites test_suite_gcm test_suite_gcm.aes256_en
+	$(PERL) scripts/generate_code.pl suites test_suite_gcm test_suite_gcm.aes256_en
 
 test_suite_gcm.camellia.c : suites/test_suite_gcm.function suites/test_suite_gcm.camellia.data scripts/generate_code.pl suites/helpers.function suites/main_test.function
 	echo   "  Generate	$@"
-	scripts/generate_code.pl suites test_suite_gcm test_suite_gcm.camellia
+	$(PERL) scripts/generate_code.pl suites test_suite_gcm test_suite_gcm.camellia
 
 test_suite_hmac_drbg.misc.c : suites/test_suite_hmac_drbg.function suites/test_suite_hmac_drbg.misc.data scripts/generate_code.pl suites/helpers.function suites/main_test.function
 	echo   "  Generate	$@"
-	scripts/generate_code.pl suites test_suite_hmac_drbg test_suite_hmac_drbg.misc
+	$(PERL) scripts/generate_code.pl suites test_suite_hmac_drbg test_suite_hmac_drbg.misc
 
 test_suite_hmac_drbg.no_reseed.c : suites/test_suite_hmac_drbg.function suites/test_suite_hmac_drbg.no_reseed.data scripts/generate_code.pl suites/helpers.function suites/main_test.function
 	echo   "  Generate	$@"
-	scripts/generate_code.pl suites test_suite_hmac_drbg test_suite_hmac_drbg.no_reseed
+	$(PERL) scripts/generate_code.pl suites test_suite_hmac_drbg test_suite_hmac_drbg.no_reseed
 
 test_suite_hmac_drbg.nopr.c : suites/test_suite_hmac_drbg.function suites/test_suite_hmac_drbg.nopr.data scripts/generate_code.pl suites/helpers.function suites/main_test.function
 	echo   "  Generate	$@"
-	scripts/generate_code.pl suites test_suite_hmac_drbg test_suite_hmac_drbg.nopr
+	$(PERL) scripts/generate_code.pl suites test_suite_hmac_drbg test_suite_hmac_drbg.nopr
 
 test_suite_hmac_drbg.pr.c : suites/test_suite_hmac_drbg.function suites/test_suite_hmac_drbg.pr.data scripts/generate_code.pl suites/helpers.function suites/main_test.function
 	echo   "  Generate	$@"
-	scripts/generate_code.pl suites test_suite_hmac_drbg test_suite_hmac_drbg.pr
+	$(PERL) scripts/generate_code.pl suites test_suite_hmac_drbg test_suite_hmac_drbg.pr
 
 %.c : suites/%.function suites/%.data scripts/generate_code.pl suites/helpers.function suites/main_test.function
 	echo   "  Generate	$@"
-	scripts/generate_code.pl suites $* $*
+	$(PERL) scripts/generate_code.pl suites $* $*
 
 test_suite_aes.ecb$(EXEXT): test_suite_aes.ecb.c $(DEP)
 	echo   "  CC    	$<"