Rob Sykes patch to make libsoxr build for Audacity

m4/audacity_checklib_libsoxr.m4

@@ -0,0 +1,50 @@
+dnl Add Audacity license?
+dnl Please increment the serial number below whenever you alter this macro
+dnl for the benefit of automatic macro update systems
+# audacity_checklib_libsoxr.m4 serial 1
+
+AC_DEFUN([AUDACITY_CHECKLIB_LIBSOXR], [
+
+   AC_ARG_WITH(libsoxr,
+               [AS_HELP_STRING([--with-libsoxr],
+                               [use libsoxr for sample rate conversion: [yes,no]])],
+               LIBSOXR_ARGUMENT=$withval,
+               LIBSOXR_ARGUMENT="unspecified")
+
+   if true ; then
+      AC_DEFINE(USE_LIBSOXR, 1,
+                [Define if libsoxr support should be enabled])
+   fi
+
+   dnl see if libsoxr is installed on the system
+
+   dnl ... but libsoxr isn't yet generally installed as a system library...
+
+   LIBSOXR_SYSTEM_AVAILABLE="no"
+
+   dnl see if libsoxr is available locally
+
+   AC_CHECK_FILE(${srcdir}/lib-src/libsoxr/src/soxr-lsr.h,
+                 soxr_h_found="yes",
+                 soxr_h_found="no")
+
+   if test "x$soxr_h_found" = "xyes" ; then
+      LIBSOXR_LOCAL_AVAILABLE="yes"
+      LIBSOXR_LOCAL_LIBS="libsoxr-lsr.a libsoxr.a"
+      LIBSOXR_LOCAL_CXXFLAGS='-I$(top_srcdir)/lib-src/libsoxr/src'
+      LIBSOXR_LOCAL_CPPSYMBOLS="USE_LIBSOXR"
+
+      if test ! -f lib-src/libsoxr/Makefile ; then
+         LIBSOXR_LOCAL_CONFIG_SUBDIRS="lib-src/libsoxr"
+
+         # Breaks other other libraries in Audacity tree; but why is ./configure
+         # passing options specific to this library to other libraries?
+         #LIBSOXR_LOCAL_CONFIGURE_ARGS="\"-DBUILD_SHARED_LIBS=OFF -DWITH_OPENMP=OFF\""
+      fi
+      AC_MSG_NOTICE([libsoxr libraries are available in the local tree])
+   else
+      LIBSOXR_LOCAL_AVAILABLE="no"
+      AC_MSG_NOTICE([libsoxr libraries are NOT available in the local tree])
+   fi
+])
+