contrib/samplerate: disable building tests, doc, examples

make build faster by disabling the build of
doc, examples and tests subdirectories.
Also prevent potential build errors in those directories.

Change-Id: I14e5d62831301227c7250a3aaef55db20e8343c2
Reviewed-by: Guillaume Roguez <guillaume.roguez@savoirfairelinux.com>

contrib/src/samplerate/disable_tests.patch

+From 4188b5b9e553911f562e2ae147c8d2ae17bc2500 Mon Sep 17 00:00:00 2001
+From: Adrien Beraud <adrien.beraud@savoirfairelinux.com>
+Date: Wed, 2 Aug 2017 16:42:36 -0400
+Subject: [PATCH] don't build example, doc, tests
+
+---
+ Makefile.am | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/Makefile.am b/Makefile.am
+index 1295c92..47bd97d 100644
+--- a/Makefile.am
++++ b/Makefile.am
+@@ -2,7 +2,7 @@
+ 
+ DISTCHECK_CONFIGURE_FLAGS = --enable-gcc-werror
+ 
+-SUBDIRS = M4 src doc examples tests
++SUBDIRS = M4 src
+ DIST_SUBDIRS = Win32 $(SUBDIRS)
+ 
+ EXTRA_DIST = autogen.sh libsamplerate.spec.in samplerate.pc.in Make.bat
+-- 
+2.11.0
+

contrib/src/samplerate/rules.mak

@@ -14,6 +14,7 @@ $(TARBALLS)/libsamplerate-$(SAMPLERATE_VERSION).tar.gz:
 
 samplerate: libsamplerate-$(SAMPLERATE_VERSION).tar.gz .sum-samplerate
 	$(UNPACK)
+	$(APPLY) $(SRC)/samplerate/disable_tests.patch
 	$(APPLY) $(SRC)/samplerate/soundcard.patch
 	$(APPLY) $(SRC)/samplerate/carbon.patch
 ifdef HAVE_IOS