build: mandate use of a build dir != src dir

Historically we've allowed builds in the main src dir, but meson does
not support this. Explicitly force separate build dir in autotools to
align with meson. We must re-enable dependency tracking which the RPM
%configure macro turns off. Without this, the build dir doesn't get
the source directory tree mirrored.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

.travis.yml

@@ -53,7 +53,8 @@ matrix:
       script:
         # We can't run 'distcheck' or 'syntax-check' because they fail on
         # macOS, but doing 'install' and 'dist' gives us some useful coverage
-        - ./autogen.sh --prefix=$(pwd)/install-root && make -j3 && make -j3 install && make -j3 dist
+        - mkdir build && cd build
+        - ../autogen.sh --prefix=$(pwd)/install-root && make -j3 && make -j3 install && make -j3 dist
 
 git:
   submodules: true

README-hacking

@@ -11,7 +11,7 @@ We've opted to keep only the highest-level sources in the GIT repository.
 This eases our maintenance burden, (fewer merges etc.), but imposes more
 requirements on anyone wishing to build from the just-checked-out sources.
 Note the requirements to build the released archive are much less and
-are just the requirements of the standard ./configure && make procedure.
+are just the requirements of the standard configure && make procedure.
 Specific development tools and versions will be checked for and listed by
 the bootstrap script.
 
@@ -34,10 +34,14 @@ reduce download time and disk space requirements:
 
         $ export GNULIB_SRCDIR=/path/to/gnulib
 
-The next step is to get all required pieces from gnulib,
+We require to have the build directory different than the source directory:
-to run autoreconf, and to invoke ./configure:
 
-        $ ./autogen.sh
+        $ mkdir build && cd build
+
+The next step is to get all required pieces from gnulib,
+to run autoreconf, and to invoke ../autogen.sh:
+
+        $ ../autogen.sh
 
 And there you are!  Just
 
@@ -47,6 +51,7 @@ And there you are!  Just
 At this point, there should be no difference between your local copy,
 and the GIT master copy:
 
+        $ cd ..
         $ git diff
 
 should output no difference.

README.md

@@ -38,11 +38,13 @@ Installation
 ------------
 
 Libvirt uses the GNU Autotools build system, so in general can be built
-and installed with the usual commands. For example, to build in a manner
+and installed with the usual commands, however, we mandate to have the
-that is suitable for installing as root, use:
+build directory different than the source directory. For example, to build
+in a manner that is suitable for installing as root, use:
 
 ```
-$ ./configure --prefix=/usr --sysconfdir=/etc --localstatedir=/var
+$ mkdir build && cd build
+$ ../configure --prefix=/usr --sysconfdir=/etc --localstatedir=/var
 $ make
 $ sudo make install
 ```
@@ -50,7 +52,8 @@ $ sudo make install
 While to build & install as an unprivileged user
 
 ```
-$ ./configure --prefix=$HOME/usr
+$ mkdir build && cd build
+$ ../configure --prefix=$HOME/usr
 $ make
 $ make install
 ```

bootstrap.conf

@@ -164,3 +164,9 @@ bootstrap_post_import_hook()
   sed 's,\.\./\.\./\.\.,../..,g; s/^TESTS /GNULIB_TESTS /' $m > $m-t
   mv -f $m-t $m
 }
+
+bootstrap_epilogue()
+{
+    echo "$0: done.  Now you can run 'mkdir build && cd build && ../configure'."
+    exit 0
+}

configure.ac

@@ -17,6 +17,12 @@ dnl License along with this library.  If not, see
 dnl <http://www.gnu.org/licenses/>.
 
 AC_INIT([libvirt], [5.10.0], [libvir-list@redhat.com], [], [https://libvirt.org])
+
+if test $srcdir = "."
+then
+  AC_MSG_ERROR([Build directory must be different from source directory])
+fi
+
 AC_CONFIG_SRCDIR([src/libvirt.c])
 AC_CONFIG_AUX_DIR([build-aux])
 AC_CONFIG_HEADERS([config.h])

docs/compiling.html.in

@@ -9,13 +9,15 @@
     <h2><a id="compiling">Compiling a release tarball</a></h2>
 
     <p>
-      libvirt uses the standard configure/make/install steps:
+      libvirt uses the standard configure/make/install steps and mandates
+      that the build directory is different that the source directory:
     </p>
 
     <pre>
 $ xz -c libvirt-x.x.x.tar.xz | tar xvf -
 $ cd libvirt-x.x.x
-$ ./configure</pre>
+$ mkdir build &amp;&amp; cd build
+$ ../configure</pre>
 
     <p>
       The <i>configure</i> script can be given options to change its default
@@ -28,7 +30,7 @@ $ ./configure</pre>
     </p>
 
     <pre>
-$ ./configure <i>--help</i></pre>
+$ ../configure <i>--help</i></pre>
 
     <p>
       When you have determined which options you want to use (if any),
@@ -49,7 +51,7 @@ $ ./configure <i>--help</i></pre>
     </p>
 
     <pre>
-$ ./configure <i>[possible options]</i>
+$ ../configure <i>[possible options]</i>
 $ make
 $ <b>sudo</b> <i>make install</i></pre>
 

docs/windows.html.in

@@ -180,7 +180,8 @@
     </p>
 
 <pre>
-./configure \
+mkdir build &amp;&amp; cd build
+../configure \
   --without-sasl \
   --without-polkit \
   --without-python \

libvirt.spec.in

@@ -1163,7 +1163,13 @@ export SOURCE_DATE_EPOCH=$(stat --printf='%Y' %{_specdir}/%{name}.spec)
 %endif
 
 rm -f po/stamp-po
-%configure --with-runstatedir=%{_rundir} \
+
+%define _configure ../configure
+mkdir %{_vpath_builddir}
+cd %{_vpath_builddir}
+
+%configure --enable-dependency-tracking \
+           --with-runstatedir=%{_rundir} \
            %{?arg_qemu} \
            %{?arg_openvz} \
            %{?arg_lxc} \
@@ -1232,6 +1238,7 @@ rm -fr %{buildroot}
 
 export SOURCE_DATE_EPOCH=$(stat --printf='%Y' %{_specdir}/%{name}.spec)
 
+cd %{_vpath_builddir}
 %make_install %{?_smp_mflags} SYSTEMD_UNIT_DIR=%{_unitdir} V=1
 
 rm -f $RPM_BUILD_ROOT%{_libdir}/*.la
@@ -1313,6 +1320,7 @@ mv $RPM_BUILD_ROOT%{_datadir}/systemtap/tapset/libvirt_qemu_probes.stp \
 %endif
 
 %check
+cd %{_vpath_builddir}
 if ! make %{?_smp_mflags} check VIR_TEST_DEBUG=1
 then
   cat test-suite.log || true