Bug#960093: audacity FTCBFS: wrong use of AC_CHECK_FILE for portmidi

[Helmut Grohne <helmut@subdivi.de>]

Source: audacity
Version: 2.3.3-2
Tags: patch upstream
User: debian-cross@lists.debian.org
Usertags: ftcbfs

Since fixing #850463, a new AC_CHECK_FILE was introduced. Please
consider applying the attached patch to fix that as well.

Helmut

--- audacity-2.3.3.orig/m4/audacity_checklib_portmidi.m4
+++ audacity-2.3.3/m4/audacity_checklib_portmidi.m4
@@ -21,7 +21,7 @@
       AC_MSG_NOTICE([portmidi library is NOT available as system library])
    fi
 
-   AC_CHECK_FILE(${srcdir}/lib-src/portmidi/pm_common/portmidi.h,
+   AS_IF([test -f "${srcdir}/lib-src/portmidi/pm_common/portmidi.h"],
                  PORTMIDI_LOCAL_AVAILABLE="yes",
                  PORTMIDI_LOCAL_AVAILABLE="no")