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
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<div class='path'>path: <a href='/guix/log/?id=b6933ea634f5522e64a61c83771fa28b78948acd'>root</a>/<a href='/guix/log/gnu?id=b6933ea634f5522e64a61c83771fa28b78948acd'>gnu</a>/<a href='/guix/log/gnu/packages?id=b6933ea634f5522e64a61c83771fa28b78948acd'>packages</a>/<a href='/guix/log/gnu/packages/datastructures.scm?id=b6933ea634f5522e64a61c83771fa28b78948acd'>datastructures.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/gnu/packages/datastructures.scm?id=b6933ea634f5522e64a61c83771fa28b78948acd&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2019-01-26 14:46:40 +0100'>2019-01-26</span></td><td><a href='/guix/commit/gnu/packages/datastructures.scm?id=c9e75159706368be7b0b9d8a8fe33dc2786e37a7'>gnu: uthash: Use INVOKE.</a><span class='msg-avail'>...</span></td><td>Ricardo Wurmus</td></tr>
<tr><td><span title='2019-01-26 14:46:05 +0100'>2019-01-26</span></td><td><a href='/guix/commit/gnu/packages/datastructures.scm?id=d1293d426dcfb711a8c156ff66b7cdc93ff32fef'>gnu: uthash: Fetch sources via git.</a><span class='msg-avail'>...</span></td><td>Ricardo Wurmus</td></tr>
<tr><td><span title='2019-01-19 00:03:23 +0100'>2019-01-19</span></td><td><a href='/guix/commit/gnu/packages/datastructures.scm?id=3a1d01ca324c9cba55a33fb1f0d9007cc01e65da'>gnu: liburcu: Update to 0.10.2.</a><span class='msg-avail'>...</span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2019-01-19 00:03:14 +0100'>2019-01-19</span></td><td><a href='/guix/commit/gnu/packages/datastructures.scm?id=4dfda8dce065c199216b452fe48ac73405893a47'>gnu: liburcu: Use HTTPS home page.</a><span class='msg-avail'>...</span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2019-01-07 11:56:14 +0100'>2019-01-07</span></td><td><a href='/guix/commit/gnu/packages/datastructures.scm?id=ad6f13308b1b3ee38ef76482bc597d9a9e1a31c2'>gnu: Add sdsl-lite.</a><span class='msg-avail'>...</span></td><td>Ricardo Wurmus</td></tr>
<tr><td><span title='2018-11-10 23:33:46 +0100'>2018-11-10</span></td><td><a href='/guix/commit/gnu/packages/datastructures.scm?id=9d466489cdbbfb2097ec3e211351d7b34fb70b60'>gnu: Add marisa.</a><span class='msg-avail'>...</span></td><td>Meiyo Peng</td></tr>
<tr><td><span title='2018-01-24 15:47:52 +0100'>2018-01-24</span></td><td><a href='/guix/commit/gnu/packages/datastructures.scm?id=8f4bf6a99065f836858c42ebcd2ee8a6c4482c65'>gnu: liburcu: Update to 0.10.1.</a><span class='msg-avail'>...</span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2017-12-12 05:12:13 +0100'>2017-12-12</span></td><td><a href='/guix/commit/gnu/packages/datastructures.scm?id=cc3ac162c558a51c90b76b84b081a15e28d0baad'>gnu: Add uthash.</a><span class='msg-avail'>...</span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2017-06-15 10:34:22 +0200'>2017-06-15</span></td><td><a href='/guix/commit/gnu/packages/datastructures.scm?id=a3f8aae4a159baf2de10c1f8860d7128c89fbb0c'>gnu: liburcu: Update to 0.10.0.</a><span class='msg-avail'>...</span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2017-04-17 02:04:08 +0200'>2017-04-17</span></td><td><a href='/guix/commit/gnu/packages/datastructures.scm?id=d1e4ad1b02b2ea888557d3272c50b676faf18ca4'>gnu: Fix typos in descriptions.</a><span class='msg-avail'>...</span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2017-03-17 02:32:00 +0100'>2017-03-17</span></td><td><a href='/guix/commit/gnu/packages/datastructures.scm?id=754667f0eb44491370a2ec4fa0b4705cfcf6d237'>gnu: Add liburcu.</a><span class='msg-avail'>...</span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2016-07-19 23:03:30 +0200'>2016-07-19</span></td><td><a href='/guix/commit/gnu/packages/datastructures.scm?id=592ccdd38850d581f669f834f051ee8f92d7ee31'>gnu: Add ssdeep.</a><span class='msg-avail'>...</span></td><td>Tobias Geerinckx-Rice</td></tr>