configure: Disable portability to cater to code-coverage

Avoid a mass of warnings from automake. We will reassess if portability
ever becomes a necessary property.

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Change-Id: I2fb620c0471aac4ff6712383880509bbf0ab0d9e
diff --git a/configure.ac b/configure.ac
index 3a2343b..3cde609 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3,7 +3,7 @@
 AC_INIT([libmctp], 0.9, [https://github.com/openbmc/libmctp/issues])
 AC_CONFIG_HEADERS([config.h])
 AC_CONFIG_MACRO_DIRS([m4])
-AM_INIT_AUTOMAKE([subdir-objects -Wall -Werror foreign dist-xz])
+AM_INIT_AUTOMAKE([subdir-objects -Wall -Werror -Wno-portability foreign dist-xz])
 AM_SILENT_RULES([yes])
 
 # Checks for programs.