build: enable C++20

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I0caac0e64dc05bbd9bdeeb12daa04d24f2aadea0
diff --git a/configure.ac b/configure.ac
index f2be82d..4a1e6f7 100644
--- a/configure.ac
+++ b/configure.ac
@@ -22,7 +22,7 @@
 [AC_MSG_ERROR([Minimum python version(3) not found])])
 
 # Checks for typedefs, structures, and compiler characteristics.
-AX_CXX_COMPILE_STDCXX_17([noext])
+AX_CXX_COMPILE_STDCXX([20],[noext])
 AX_APPEND_COMPILE_FLAGS([-Wall -Werror], [CXXFLAGS])
 
 # Checks for libraries.