procmail: Add -std=gnu17 to fix error of do_compile

Without the option , the command  procmail|lockfile|formail will not be installed to target.

Signed-off-by: Wang Mingyu <wangmy@fujitsu.com>
Signed-off-by: Khem Raj <khem.raj@oss.qualcomm.com>

meta-oe/recipes-support/procmail/procmail_3.24.bb

@@ -32,7 +32,7 @@ do_configure() {
 }
 
 do_compile() {
-    oe_runmake -i CFLAGS="$TARGET_CFLAGS -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 LOCKINGTEST=/tmp" LDFLAGS0="${LDFLAGS}" LOCKINGTEST=100
+    oe_runmake -i CFLAGS="$TARGET_CFLAGS -std=gnu17 -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 LOCKINGTEST=/tmp" LDFLAGS0="${LDFLAGS}" LOCKINGTEST=100
 }
 
 do_install() {