[PATCH] lib, ruby: make use of -Wl,--no-undefined configurable

[Jinwoo Lee]

Turns out my previous error was because I was running tests within Emacs
eshell, and run_emacs failed.

I tried again in a terminal and it still failed but for a different
reason.  I don't have readelf on my Mac.

$ make test
/Applications/Xcode.app/Contents/Developer/usr/bin/make -C .. test
cd bindings/ruby && \
		EXTRA_LDFLAGS="" \
		LIBNOTMUCH="../../lib/libnotmuch.dylib" \
		ruby extconf.rb --vendor
creating Makefile
/Applications/Xcode.app/Contents/Developer/usr/bin/make -C bindings/ruby
linking shared-object notmuch.bundle
ld: warning: directory not found for option '-L/usr/local/lib'
ld: warning: directory not found for option '-L/usr/local/lib'
ld: warning: ignoring file ../../lib/libnotmuch.dylib, file was built for x86_64 which is not the architecture being linked (i386): ../../lib/libnotmuch.dylib
INFO: using 2 minute timeout for tests

T000-basic: Testing the test framework itself.
./test-lib-common.sh: line 43: /Users/jinwoo/Box: No such file or directory
 PASS   success is reported like this
 PASS   test runs if prerequisite is satisfied
 PASS   tests clean up after themselves
 PASS   tests clean up even after a failure
 PASS   failure to clean up causes the test to fail
 PASS   Ensure that test output is suppressed unless the test fails
 PASS   Ensure that -v does not suppress test output
 PASS   test that mail store was created
 PASS   mail store should be empty
 PASS   NOTMUCH_CONFIG is set and points to an existing file
 FAIL   PATH is set to build directory
	--- T000-basic.11.expected	2015-06-16 23:40:30.000000000 +0000
	+++ T000-basic.11.output	2015-06-16 23:40:30.000000000 +0000
	@@ -1 +1 @@
	-/Users/jinwoo/Box Sync/personal/project/notmuch
	+
usage: dirname path
 FAIL   notmuch is compiled with debugging symbols
	--- T000-basic.12.expected	2015-06-16 23:40:30.000000000 +0000
	+++ T000-basic.12.output	2015-06-16 23:40:30.000000000 +0000
	@@ -1 +1 @@
	-1
	+0
./T000-basic.sh: line 95: readelf: command not found
./test-lib.sh: line 1062: $test_results_path: ambiguous redirect
./test-lib.sh: line 1063: $test_results_path: ambiguous redirect
./test-lib.sh: line 1064: $test_results_path: ambiguous redirect
./test-lib.sh: line 1065: $test_results_path: ambiguous redirect
./test-lib.sh: line 1066: $test_results_path: ambiguous redirect
./test-lib.sh: line 1067: $test_results_path: ambiguous redirect
make[1]: *** [test] Error 1
make: *** [test] Error 2