Rearrange configure.ac a bit

Anything that uses gcc needs to happen after we've made the mingw
inplace tree on Windows.

configure.ac

@@ -86,62 +86,6 @@ AC_ARG_WITH([ghc],
   fi
   WithGhc="$GHC"])
 
-# system libffi
-
-AC_ARG_WITH([system-libffi],
-[AC_HELP_STRING([--with-system-libffi],
-  [Use system provided libffi for RTS [default=no]])
-])
-
-AS_IF([test "x$with_system_libffi" = "xyes"],
-  [UseSystemLibFFI="YES"], [UseSystemLibFFI="NO"]
-)
-
-
-AC_SUBST(UseSystemLibFFI)
-
-AC_ARG_WITH([ffi-includes],
-[AC_HELP_STRING([--with-ffi-includes=ARG]
-  [Find includes for libffi in ARG [default=system default]])
-],
-[
- if test "x$UseSystemLibFFI" != "xYES"; then
-    AC_MSG_WARN([--with-ffi-includes will be ignored, --with-system-libffi not set])
- else
-    FFIIncludeDir="$withval"
-    LIBFFI_CFLAGS="-I $withval" 
- fi
-])
-
-AC_SUBST(FFIIncludeDir)
-
-AC_ARG_WITH([ffi-libraries],
-[AC_HELP_STRING([--with-ffi-libraries=ARG]
-  [Find libffi in ARG [default=system default]])
-],
-[
- if test "x$UseSystemLibFFI" != "xYES"; then
-    AC_MSG_WARN([--with-ffi-libraries will be ignored, --with-system-libffi not set])
- else
-    FFILibDir="$withval" LIBFFI_LDFLAGS="-L$withval"
- fi
-])
-
-AC_SUBST(FFILibDir)
-
-AS_IF([test "$UseSystemLibFFI" = "YES"], [
- CFLAGS2="$CFLAGS"
- CFLAGS="$LIBFFI_CFLAGS $CFLAGS"
- LDFLAGS2="$LDFLAGS"
- LDFLAGS="$LIBFFI_LDFLAGS $LDFLAGS"
- AC_CHECK_LIB(ffi, ffi_call,
-  [AC_CHECK_HEADERS([ffi.h], [break], [])
-   AC_DEFINE([HAVE_LIBFFI], [1], [Define to 1 if you have libffi.])],
-  [AC_MSG_ERROR([Cannot find system libffi])])
- CFLAGS="$CFLAGS2"
- LDFLAGS="$LDFLAGS2"
-])
-
 dnl ** Tell the make system which OS we are using
 dnl $OSTYPE is set by the operating system to "msys" or "cygwin" or something 
 AC_SUBST(OSTYPE)
@@ -241,9 +185,6 @@ AC_SUBST([WithGhc])
 dnl ** Without optimization some INLINE trickery fails for GHCi
 SRC_CC_OPTS="-O"
 
-FP_ICONV
-FP_GMP
-
 dnl--------------------------------------------------------------------
 dnl * Choose host(/target/build) platform
 dnl--------------------------------------------------------------------
@@ -428,6 +369,65 @@ then
     fi
 fi
 
+# system libffi
+
+AC_ARG_WITH([system-libffi],
+[AC_HELP_STRING([--with-system-libffi],
+  [Use system provided libffi for RTS [default=no]])
+])
+
+AS_IF([test "x$with_system_libffi" = "xyes"],
+  [UseSystemLibFFI="YES"], [UseSystemLibFFI="NO"]
+)
+
+
+AC_SUBST(UseSystemLibFFI)
+
+AC_ARG_WITH([ffi-includes],
+[AC_HELP_STRING([--with-ffi-includes=ARG]
+  [Find includes for libffi in ARG [default=system default]])
+],
+[
+ if test "x$UseSystemLibFFI" != "xYES"; then
+    AC_MSG_WARN([--with-ffi-includes will be ignored, --with-system-libffi not set])
+ else
+    FFIIncludeDir="$withval"
+    LIBFFI_CFLAGS="-I $withval" 
+ fi
+])
+
+AC_SUBST(FFIIncludeDir)
+
+AC_ARG_WITH([ffi-libraries],
+[AC_HELP_STRING([--with-ffi-libraries=ARG]
+  [Find libffi in ARG [default=system default]])
+],
+[
+ if test "x$UseSystemLibFFI" != "xYES"; then
+    AC_MSG_WARN([--with-ffi-libraries will be ignored, --with-system-libffi not set])
+ else
+    FFILibDir="$withval" LIBFFI_LDFLAGS="-L$withval"
+ fi
+])
+
+AC_SUBST(FFILibDir)
+
+AS_IF([test "$UseSystemLibFFI" = "YES"], [
+ CFLAGS2="$CFLAGS"
+ CFLAGS="$LIBFFI_CFLAGS $CFLAGS"
+ LDFLAGS2="$LDFLAGS"
+ LDFLAGS="$LIBFFI_LDFLAGS $LDFLAGS"
+ AC_CHECK_LIB(ffi, ffi_call,
+  [AC_CHECK_HEADERS([ffi.h], [break], [])
+   AC_DEFINE([HAVE_LIBFFI], [1], [Define to 1 if you have libffi.])],
+  [AC_MSG_ERROR([Cannot find system libffi])])
+ CFLAGS="$CFLAGS2"
+ LDFLAGS="$LDFLAGS2"
+])
+
+FP_ICONV
+FP_GMP
+
 XCODE_VERSION()
 
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