diff --git a/src/tasks/gtest.cpp b/src/tasks/gtest.cpp
index c50cab8..65f34ae 100644
--- a/src/tasks/gtest.cpp
+++ b/src/tasks/gtest.cpp
@@ -14,6 +14,7 @@ cmake create_cmake_tool(arch a, cmake::ops o=cmake::generate)
 	return std::move(cmake(o)
 		.generator(cmake::vs)
 		.architecture(a)
+		.arg("-Wno-deprecated")
 		.prefix(gtest::source_path() / build_dir)
 		.root(gtest::source_path()));
 }
diff --git a/src/tasks/zlib.cpp b/src/tasks/zlib.cpp
index ed1e1cb..2a8950a 100644
--- a/src/tasks/zlib.cpp
+++ b/src/tasks/zlib.cpp
@@ -87,6 +87,7 @@ cmake zlib::create_cmake_tool(cmake::ops o)
 	return std::move(cmake(o)
 		.generator(cmake::vs)
 		.root(source_path())
+		.arg("-Wno-deprecated")
 		.prefix(source_path()));
 }
 
diff --git a/src/tools/cmake.cpp b/src/tools/cmake.cpp
index e763b6d..09d4e21 100644
--- a/src/tools/cmake.cpp
+++ b/src/tools/cmake.cpp
@@ -47,7 +47,7 @@ cmake& cmake::prefix(const fs::path& s)
 
 cmake& cmake::def(const std::string& name, const std::string& value)
 {
-	def_.emplace_back(name, value);
+	arg("-D" + name + "=" + value);
 	return *this;
 }
 
@@ -63,6 +63,12 @@ cmake& cmake::def(const std::string& name, const char* s)
 	return *this;
 }
 
+cmake& cmake::arg(std::string s)
+{
+	args_.push_back(std::move(s));
+	return *this;
+}
+
 cmake& cmake::architecture(arch a)
 {
 	arch_ = a;
@@ -150,9 +156,7 @@ void cmake::do_generate()
 	if (!prefix_.empty())
 		p.arg("-DCMAKE_INSTALL_PREFIX=", prefix_);
 
-	// macros
-	for (auto&& [name, value] : def_)
-		p.arg("-D" + name + "=" + value + "");
+	p.args(args_);
 
 	// `..` by default, overriden by cmd()
 	if (cmd_.empty())
diff --git a/src/tools/cmake.h b/src/tools/cmake.h
index 1107594..021e8df 100644
--- a/src/tools/cmake.h
+++ b/src/tools/cmake.h
@@ -79,6 +79,10 @@ public:
 	cmake& def(const std::string& name, const fs::path& p);
 	cmake& def(const std::string& name, const char* s);
 
+	// adds an arbitrary argument, passed verbatim
+	//
+	cmake& arg(std::string s);
+
 	// sets the architecture, used along with the generator to create the
 	// output directory name, but also to get the proper vcvars environment
 	// variables for the build environment
@@ -149,8 +153,8 @@ private:
 	// passed as -DCMAKE_INSTALL_PREFIX
 	fs::path prefix_;
 
-	// passed as -Dkey=value
-	std::vector<std::pair<std::string, std::string>> def_;
+	// passed verbatim
+	std::vector<std::string> args_;
 
 	// overrides build directory name
 	fs::path output_;