diff --git a/configure.py b/configure.py
index 79aefe6ac2..eeab0cded0 100755
--- a/configure.py
+++ b/configure.py
@@ -1839,7 +1839,7 @@ def write_build_file(f,
         configure_args = {configure_args}
         builddir = {outdir}
         cxx = {cxx}
-        cxxflags = --std=gnu++20 {user_cflags} {warnings} {defines}
+        cxxflags = -std=gnu++20 {user_cflags} {warnings} {defines}
         ldflags = {linker_flags} {user_ldflags}
         ldflags_build = {linker_flags}
         libs = {libs}