Backed out changeset 9b8f326731ac

Unfortunately, disabling the rust extensions means newer
Mercurial versions no longer have the persistent-nodemap
feature enabled.
This means a Mercurial 5.8.1 on RPM-based Linux distributions
will no longer be able to read repositories created
by a Mercurial 5.8 on RPM-based Linux distributions.

This violates the compatibility rules
(see https://www.mercurial-scm.org/wiki/CompatibilityRules ).

For this reason, I have to backout this change.
I'll try to find another solution to the 'hg purge' crashes.

Differential Revision: https://phab.mercurial-scm.org/D10918

contrib/packaging/docker/centos7

@@ -15,3 +15,6 b' RUN yum install -y \\'
 
 # For creating repo meta data
 RUN yum install -y createrepo
+
+# For rust extensions
+RUN yum install -y cargo

contrib/packaging/docker/centos8

@@ -13,3 +13,6 b' RUN yum install -y \\'
 
 # For creating repo meta data
 RUN yum install -y createrepo
+
+# For rust extensions
+RUN yum install -y cargo

contrib/packaging/mercurial.spec

@@ -110,14 +110,14 b' cd %{docutilsname}'
 LD_LIBRARY_PATH=$PYPATH $PYPATH/python setup.py install --root="$RPM_BUILD_ROOT"
 cd -
 
-PATH=$PYPATH:$PATH LD_LIBRARY_PATH=$PYPATH make install PYTHON=%{pythonexe} DESTDIR=$RPM_BUILD_ROOT PREFIX=%{hgpyprefix} MANDIR=%{_mandir}
+PATH=$PYPATH:$PATH LD_LIBRARY_PATH=$PYPATH make install PYTHON=%{pythonexe} DESTDIR=$RPM_BUILD_ROOT PREFIX=%{hgpyprefix} MANDIR=%{_mandir} PURE="--rust"
 mkdir -p $RPM_BUILD_ROOT%{_bindir}
 ( cd $RPM_BUILD_ROOT%{_bindir}/ && ln -s ../..%{hgpyprefix}/bin/hg . )
 ( cd $RPM_BUILD_ROOT%{_bindir}/ && ln -s ../..%{hgpyprefix}/bin/python2.? %{pythonhg} )
 
 %else
 
-make install PYTHON=%{pythonexe} DESTDIR=$RPM_BUILD_ROOT PREFIX=%{_prefix} MANDIR=%{_mandir}
+make install PYTHON=%{pythonexe} DESTDIR=$RPM_BUILD_ROOT PREFIX=%{_prefix} MANDIR=%{_mandir} PURE="--rust"
 
 %endif