diff --git a/Crafter.Build-ModuleFile.cpp b/Crafter.Build-ModuleFile.cpp
index 0ba86bd..418c8f2 100644
--- a/Crafter.Build-ModuleFile.cpp
+++ b/Crafter.Build-ModuleFile.cpp
@@ -163,6 +163,12 @@ void Module::Check() {
 }
 
 void Module::Compile(std::string clangDir, const Configuration& config, fs::path pcmDir, std::string target, const std::string& march, const std::string& flags, const fs::path& buildDir) {
+    
+    std::string defines;
+    for(const Define& define : config.defines) {
+        defines+=define.ToString();
+    }
+    
     std::vector<std::thread> threads;
     for(auto& [key, val] : partitions) {;
         if(val.needsRecompiling) {
@@ -177,7 +183,7 @@ void Module::Compile(std::string clangDir, const Configuration& config, fs::path
     }
 
     {
-        std::string command = std::format("{} {} -std={} {}.cppm --precompile {} -fprebuilt-module-path={} -o {}.pcm {}", clangDir, flags, config.standard, path.generic_string(), march, pcmDir.generic_string(), (pcmDir/path.filename()).generic_string(), target);
+        std::string command = std::format("{} {} {} -std={} {}.cppm --precompile {} -fprebuilt-module-path={} -o {}.pcm {}", clangDir, defines, flags, config.standard, path.generic_string(), march, pcmDir.generic_string(), (pcmDir/path.filename()).generic_string(), target);
         if(config.verbose) {
             std::cout << command << std::endl;
         }
@@ -193,7 +199,7 @@ void Module::Compile(std::string clangDir, const Configuration& config, fs::path
         }
     }
     threads2.emplace_back([this, &clangDir, &config, &pcmDir, &target, &march, &flags, &buildDir](){
-        std::string command = std::format("{} -std={} {}.pcm -fprebuilt-module-path={} -c -O{} {} {} -o {}.o {}", clangDir, config.standard, (pcmDir/path.filename()).generic_string(), pcmDir.generic_string(), config.optimizationLevel, march, flags, (buildDir/path.filename()).generic_string(), target);
+        std::string command = std::format("{} {} -std={} {}.pcm -fprebuilt-module-path={} -c -O{} {} {} -o {}.o {}", clangDir, defines, config.standard, (pcmDir/path.filename()).generic_string(), pcmDir.generic_string(), config.optimizationLevel, march, flags, (buildDir/path.filename()).generic_string(), target);
         if(config.verbose) {
             std::cout << command << std::endl;
         }