build: fix gcc warning requiring Wformat

On some CentOS/RHEL systems using gcc 8.3.1 to compile dpdk, gcc shows a
warning on every build step saying that -Wformat-nonliteral and
-Wformat-security warnings will be ignored unless -Wformat is
also specified as a compiler flag. When the build is run with -werror
the build will fail due to these warnings.

Exact warning returned:
cc1: error: -Wformat-nonliteral ignored without -Wformat
[-Werror=format-nonliteral]
cc1: error: -Wformat-security ignored without -Wformat
[-Werror=format-security]
cc1: all warnings being treated as errors

This patch adds the -Wformat flag to config/meson.build. The warning id
181 has also been suppressed in icc as icc was showing false positives
with -Wformat enabled.

Fixes: 524a0d5d66 ("build: enable extra warnings with meson")
Cc: stable@dpdk.org

Signed-off-by: Conor Walsh <conor.walsh@intel.com>
Tested-by: Lingli Chen <linglix.chen@intel.com>

config/meson.build

@@ -194,6 +194,7 @@ warning_flags = [
 	# additional warnings in alphabetical order
 	'-Wcast-qual',
 	'-Wdeprecated',
+	'-Wformat',
 	'-Wformat-nonliteral',
 	'-Wformat-security',
 	'-Wmissing-declarations',
@@ -220,7 +221,7 @@ if not dpdk_conf.get('RTE_ARCH_64')
 	warning_flags += '-Wno-pointer-to-int-cast'
 endif
 if cc.get_id() == 'intel'
-	warning_ids = [188, 2203, 2279, 2557, 3179, 3656]
+	warning_ids = [181, 188, 2203, 2279, 2557, 3179, 3656]
 	foreach i:warning_ids
 		warning_flags += '-diag-disable=@0@'.format(i)
 	endforeach