Disable TLF fonts to build with mingw32 in travis

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>

.travis.yml

@@ -16,7 +16,7 @@ matrix:
   include:
     - os: linux
       compiler: i586-mingw32msvc-gcc
-      script: make CC="$CC" LD="$CC"
+      script: make CC="$CC" XCFLAGS= LD="$CC"
     - os: linux
       compiler: '"clang -fsanitize=address"'
       script: make CC="$CC" LD="$CC" && make check