diff --git a/cmake/MDEBase.cmake b/cmake/MDEBase.cmake
index d1ee595..0ef9d3d 100644
--- a/cmake/MDEBase.cmake
+++ b/cmake/MDEBase.cmake
@@ -1,3 +1,4 @@
+include_guard(DIRECTORY)
 include(GNUInstallDirs)
 
 macro(setup_project name dir)
@@ -27,3 +28,13 @@ macro(setup_project name dir)
 		DESTINATION ${dir}
 	)
 endmacro()
+
+macro(math_add name)
+	if(NOT CMAKE_SYSTEM_NAME STREQUAL "Windows")
+		target_link_libraries(
+			${name}
+			PRIVATE
+			m
+		)
+	endif()
+endmacro()
diff --git a/cmake/MDEPkgConfig.cmake b/cmake/MDEPkgConfig.cmake
index b40e6a6..2bb23ac 100644
--- a/cmake/MDEPkgConfig.cmake
+++ b/cmake/MDEPkgConfig.cmake
@@ -1,3 +1,4 @@
+include_guard(DIRECTORY)
 find_package(PkgConfig)
 
 macro(pkg_config_add dest name)