From cc7b68a365fe8afae781937f781fe90d69f4ebdc Mon Sep 17 00:00:00 2001
From: Ben Clayton <bclayton@google.com>
Date: Mon, 2 Dec 2019 13:43:14 +0000
Subject: [PATCH] CMakeLists.txt: Make it easier to control options from
 dependee projects.

---
 CMakeLists.txt | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index b8eda57..ac15424 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -22,14 +22,20 @@ project(cppdap C CXX)
 ###########################################################
 # Options
 ###########################################################
-option(CPPDAP_WARNINGS_AS_ERRORS "Treat warnings as errors" OFF)
-option(CPPDAP_BUILD_EXAMPLES "Build example applications" OFF)
-option(CPPDAP_BUILD_TESTS "Build tests" OFF)
-option(CPPDAP_ASAN "Build dap with address sanitizer" OFF)
-option(CPPDAP_MSAN "Build dap with memory sanitizer" OFF)
-option(CPPDAP_TSAN "Build dap with thread sanitizer" OFF)
-option(CPPDAP_INSTALL_VSCODE_EXAMPLES "Build and install dap examples into vscode extensions directory" OFF)
-option(CPPDAP_INSTALL "Create dap install target" OFF)
+function (option_if_not_defined name description default)
+    if(NOT DEFINED ${name})
+        option(${name} ${description} ${default})
+    endif()
+endfunction()
+
+option_if_not_defined(CPPDAP_WARNINGS_AS_ERRORS "Treat warnings as errors" OFF)
+option_if_not_defined(CPPDAP_BUILD_EXAMPLES "Build example applications" OFF)
+option_if_not_defined(CPPDAP_BUILD_TESTS "Build tests" OFF)
+option_if_not_defined(CPPDAP_ASAN "Build dap with address sanitizer" OFF)
+option_if_not_defined(CPPDAP_MSAN "Build dap with memory sanitizer" OFF)
+option_if_not_defined(CPPDAP_TSAN "Build dap with thread sanitizer" OFF)
+option_if_not_defined(CPPDAP_INSTALL_VSCODE_EXAMPLES "Build and install dap examples into vscode extensions directory" OFF)
+option_if_not_defined(CPPDAP_INSTALL "Create dap install target" OFF)
 
 ###########################################################
 # Directories