gnu: libreoffice.scm: Fix build failures with GCC7.

* gnu/packages/libreoffice.scm (libwpd, libcmis, libpagemaker)[arguments]: Add
"--disable-werror" to #:configure-flags.

gnu/packages/libreoffice.scm

@@ -181,6 +181,8 @@ spreadsheets and presentations.")
       (sha256 (base32
                "0436gnidx45a9vx114hhh216jrh57mqb9zyssyjfadagmyz6hgrj"))))
     (build-system gnu-build-system)
+    (arguments
+     `(#:configure-flags '("--disable-werror")))
     (native-inputs
      `(("doxygen" ,doxygen)
        ("pkg-config" ,pkg-config)))
@@ -315,6 +317,8 @@ working with graphics in the WPG (WordPerfect Graphics) format.")
           ;; FIXME: Man pages generation requires docbook-to-man; reenable
           ;; it once this is available.
           "--without-man"
+          ;; XXX: A configure test fails with GCC7 when including Boost headers.
+          "--disable-werror"
           ;; During configure, the boost headers are found, but linking
           ;; fails without the following flag.
           (string-append "--with-boost="
@@ -565,6 +569,8 @@ Java.")
       (sha256 (base32
                "17ai8ajffr0ixxmmcv3k5vgjlcsix38ldb4fw2arild70pbsrbb6"))))
     (build-system gnu-build-system)
+    (arguments
+     `(#:configure-flags '("--disable-werror")))
     (native-inputs
      `(("doxygen" ,doxygen)
        ("pkg-config" ,pkg-config)))