travis-ci: replace openmpi with mpich

Incorporate mpich into the travis-ci environment, so we can test
simple-v1 PMI support, and also Flux being launched by mpiexec/hydra.

Unfortunately we cannot apt-get the mpich package because it has not
been whitelisted for use within travis, so fetch and build it with
travis-dep-builder.

There is a known issue with clang segfaulting while building mpich.
Work around this by setting CC=gcc in travis-dep-builder, so that
dependent packages are built using gcc in both gcc and clang builders.

.travis.yml

@@ -24,7 +24,6 @@ addons:
  - uuid-dev
  - aspell
  - aspell-en
- - libopenmpi-dev
  - ccache
  coverity_scan:
  project:

src/test/travis-dep-builder.sh

@@ -16,10 +16,12 @@ http://download.zeromq.org/zeromq-4.0.4.tar.gz \
 http://download.zeromq.org/czmq-3.0.2.tar.gz \
 https://s3.amazonaws.com/json-c_releases/releases/json-c-0.11.tar.gz \
 http://downloads.sourceforge.net/ltp/lcov-1.10.tar.gz \
-http://www.open-mpi.org/software/hwloc/v1.11/downloads/hwloc-1.11.0.tar.gz"
+http://www.open-mpi.org/software/hwloc/v1.11/downloads/hwloc-1.11.0.tar.gz \
+http://www.mpich.org/static/downloads/3.1.4/mpich-3.1.4.tar.gz"
 
 declare -A extra_configure_opts=(\
 ["zeromq-4.0.4"]="--with-libsodium --with-libsodium-include-dir=\$prefix/include" \
+["mpich-3.1.4"]="--disable-fortran --disable-cxx --disable-maintainer-mode --disable-dependency-tracking --enable-shared --disable-wrapper-rpath" \
 )
 
 #
@@ -80,7 +82,7 @@ print_env () {
  echo "export CPPFLAGS=-I${prefix}/include"
  echo "export LDFLAGS=-L${prefix}/lib"
  echo "export PKG_CONFIG_PATH=${prefix}/lib/pkgconfig"
- echo "export PATH=${PATH}:${HOME}/.local/bin:${HOME}/local/usr/bin"
+ echo "export PATH=${PATH}:${HOME}/.local/bin:${HOME}/local/usr/bin:${HOME}/local/bin"
  luarocks path --bin
 }
 
@@ -143,7 +145,7 @@ for pkg in $downloads; do
  cd ${name} &&
  wget ${pkg} || die "Failed to download ${pkg}"
  tar --strip-components=1 -xf *.tar.gz || die "Failed to un-tar ${name}"
- test -x configure && ./configure --prefix=${prefix} \
+ test -x configure && CC=gcc ./configure --prefix=${prefix} \
  --sysconfdir=${prefix}/etc \
  ${extra_configure_opts[$name]} || : &&
  make PREFIX=${prefix} &&