fixed c90/gnu90/gnu99 tests
diff --git a/Makefile b/Makefile
index ffa7a62..1524dd4 100644
--- a/Makefile
+++ b/Makefile
@@ -82,6 +82,7 @@
 	@$(MAKE) -C $(TESTDIR) $@ > $(VOID)
 	@$(MAKE) -C $(ZWRAPDIR) $@ > $(VOID)
 	@$(MAKE) -C examples/ $@ > $(VOID)
+	@$(MAKE) -C contrib/gen_html $@ > $(VOID)
 	@$(RM) zstd$(EXT) zstdmt$(EXT) tmp*
 	@echo Cleaning completed
 
@@ -170,16 +171,16 @@
 	cd $(BUILDIR)/cmake/build ; cmake -DPREFIX:STRING=~/install_test_dir $(CMAKE_PARAMS) .. ; $(MAKE) install ; $(MAKE) uninstall
 
 c90test: clean
-	CFLAGS="-std=c90" $(MAKE) all  # will fail, due to // and long long
+	CFLAGS="-std=c90" $(MAKE) allmost  # will fail, due to missing support for `long long`
 
 gnu90test: clean
-	CFLAGS="-std=gnu90" $(MAKE) all
+	CFLAGS="-std=gnu90" $(MAKE) allmost
 
 c99test: clean
 	CFLAGS="-std=c99" $(MAKE) allmost
 
 gnu99test: clean
-	CFLAGS="-std=gnu99" $(MAKE) all
+	CFLAGS="-std=gnu99" $(MAKE) allmost
 
 c11test: clean
 	CFLAGS="-std=c11" $(MAKE) allmost