Skip tests that rely on the `amhello' tarball that comes with Automake.
That tarball's `configure' uses #!/bin/sh, but we can't easily patch it.

diff --git a/t/amhello-binpkg.sh b/t/amhello-binpkg.sh
index fa88cc6..d988cee 100755
--- a/t/amhello-binpkg.sh
+++ b/t/amhello-binpkg.sh
@@ -17,6 +17,7 @@
 # Test an example from the manual about the 'amhello' package:
 # using DESTDIR to build simple, no-frills binary packages.
 
+exit 77
 am_create_testdir=empty
 . ./defs || exit 1
 
diff --git a/t/amhello-cflags.sh b/t/amhello-cflags.sh
index 666011f..2a95e3c 100755
--- a/t/amhello-cflags.sh
+++ b/t/amhello-cflags.sh
@@ -18,6 +18,7 @@
 # using VPATH builds to configure the same package with different
 # options.
 
+exit 77
 am_create_testdir=empty
 required=gcc
 . ./defs || exit 1
diff --git a/t/amhello-cross-compile.sh b/t/amhello-cross-compile.sh
index 708abda..2ee4292 100755
--- a/t/amhello-cross-compile.sh
+++ b/t/amhello-cross-compile.sh
@@ -17,6 +17,7 @@
 # Test an example from the manual about the 'amhello' package:
 # cross-compiling a package from Linux/Unix to MinGW.
 
+exit 77
 am_create_testdir=empty
 required=i586-mingw32msvc-gcc
 . ./defs || exit 1
g/tests/networking.scm'>log</a><a href='/guix/tree/tests/networking.scm?id=65c110e27a8ce3889d0efecc36b43316265a2d8a'>tree</a><a href='/guix/commit/tests/networking.scm?id=65c110e27a8ce3889d0efecc36b43316265a2d8a'>commit</a><a href='/guix/diff/tests/networking.scm?id=65c110e27a8ce3889d0efecc36b43316265a2d8a'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/tests/networking.scm'>
<input type='hidden' name='id' value='65c110e27a8ce3889d0efecc36b43316265a2d8a'/><select name='qt'>
<option value='grep'>log msg</option>
<option value='author'>author</option>
<option value='committer'>committer</option>
<option value='range'>range</option>
</select>
<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/guix/log/?id=65c110e27a8ce3889d0efecc36b43316265a2d8a'>root</a>/<a href='/guix/log/tests?id=65c110e27a8ce3889d0efecc36b43316265a2d8a'>tests</a>/<a href='/guix/log/tests/networking.scm?id=65c110e27a8ce3889d0efecc36b43316265a2d8a'>networking.scm</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/tests/networking.scm?id=65c110e27a8ce3889d0efecc36b43316265a2d8a&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2019-10-30 18:15:54 -0400'>2019-10-30</span></td><td><a href='/guix/commit/tests/networking.scm?id=97bc3cbea5fc281a299c03eaaa3be5baf21ea673'>services: ntp: Ensure no double quotes are output to config file.</a><span class='msg-avail'>...</span></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2019-09-08 23:15:32 +0900'>2019-09-08</span></td><td><a href='/guix/commit/tests/networking.scm?id=2625abc6aa5df66a6503e906b7592691452954f5'>services: openntpd: Add test for issue #3731.</a><span class='msg-avail'>...</span></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2019-09-08 23:15:31 +0900'>2019-09-08</span></td><td><a href='/guix/commit/tests/networking.scm?id=5658ae8a0ad5d988765944b7e783b2bdc23a7f48'>services: ntp: Support different NTP server types and options.</a><span class='msg-avail'>...</span></td><td>Maxim Cournoyer</td></tr>