diff --git a/CMakeLists.txt b/CMakeLists.txt
index 24c5c81..1c68a5b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -56,6 +56,40 @@ configure_file(
   @ONLY
 )
 
+# ------------------------------------------------------------------------------
+# VA Copy check for asprintf
+# ------------------------------------------------------------------------------
+
+# Check for va_copy
+include(CheckCSourceCompiles)
+
+check_c_source_compiles("
+#include <stdarg.h>
+int main() {
+    va_list x, y;
+    va_copy(x, y);
+    return 0;
+}
+" HAVE_VA_COPY)
+
+if(HAVE_VA_COPY)
+    add_definitions(-DHAVE_VA_COPY=1)
+endif()
+
+# Check for __va_copy
+check_c_source_compiles("
+#include <stdarg.h>
+int main() {
+    va_list x, y;
+    __va_copy(x, y);
+    return 0;
+}
+" HAVE___VA_COPY)
+
+if(HAVE___VA_COPY)
+    add_definitions(-DHAVE___VA_COPY=1)
+endif()
+
 # ------------------------------------------------------------------------------
 # Clang format
 # ------------------------------------------------------------------------------