google-ipmi-sys: Build as c++17

Enables building as c++17 in the configuration.  This follows the
current guidelines to use this in OpenBMC moving forward.

Change-Id: I67495c60ae4831267f8e2ec48f63f7f6718c9426
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/configure.ac b/configure.ac
index 039060f..bb81787 100644
--- a/configure.ac
+++ b/configure.ac
@@ -13,7 +13,7 @@
 AC_PROG_MAKE_SET
 
 # Checks for typedefs, structures, and compiler characteristics.
-AX_CXX_COMPILE_STDCXX_14([noext])
+AX_CXX_COMPILE_STDCXX_17([noext])
 AX_APPEND_COMPILE_FLAGS([-Wall -Werror], [CXXFLAGS])
 
 # Checks for libraries.