flite compilation on OSX 10.13.6

README

Delete `-no-cpp-precomp` from configure and configure.in

```
git clone http://github.com/festvox/flite
cd flite
./configure CC="gcc-8"
make
make get_voices
```

diff.patch

diff --git a/configure b/configure
index 5b8a1b6..544ac09 100755
--- a/configure
+++ b/configure
@@ -4152,7 +4152,7 @@ case "$target_os" in
                 LDFLAGS="$LDFLAGS -Wl,-elf2flt"
         ;;
        darwin*)
-               CFLAGS="$CFLAGS -no-cpp-precomp"
+               CFLAGS="$CFLAGS"
        ;;
 esac
 
diff --git a/configure.in b/configure.in
index 54a782d..be936aa 100644
--- a/configure.in
+++ b/configure.in
@@ -208,7 +208,7 @@ dnl         ;;
                 LDFLAGS="$LDFLAGS -Wl,-elf2flt"
         ;;
        darwin*)
-               CFLAGS="$CFLAGS -no-cpp-precomp"
+               CFLAGS="$CFLAGS"
        ;;
 esac