Externals: Add libfmt 5.3.0 to externals

Allows us to migrate off of printf specifiers and have more type-safe
formatting facilities. It also allows for custom type support as well.
fmt is also on track to have part of it standardized within C++2a, so
this will also lessen the transitional work necessary later on by
allowing new code to use it.

This simply adds the library but doesn't do anything with it yet.

Externals/fmt/support/travis-build.py

@@ -0,0 +1,113 @@
+#!/usr/bin/env python
+# Build the project on Travis CI.
+
+from __future__ import print_function
+import errno, os, shutil, subprocess, sys, urllib
+from subprocess import call, check_call, Popen, PIPE, STDOUT
+
+def rmtree_if_exists(dir):
+    try:
+        shutil.rmtree(dir)
+    except OSError as e:
+        if e.errno == errno.ENOENT:
+            pass
+
+def makedirs_if_not_exist(dir):
+    try:
+        os.makedirs(dir)
+    except OSError as e:
+        if e.errno != errno.EEXIST:
+            raise
+
+def install_dependencies():
+    branch = os.environ['TRAVIS_BRANCH']
+    if branch != 'master':
+        print('Branch: ' + branch)
+        exit(0) # Ignore non-master branches
+    check_call('curl -s https://deb.nodesource.com/gpgkey/nodesource.gpg.key ' +
+               '| sudo apt-key add -', shell=True)
+    check_call('echo "deb https://deb.nodesource.com/node_0.10 precise main" ' +
+               '| sudo tee /etc/apt/sources.list.d/nodesource.list', shell=True)
+    check_call(['sudo', 'apt-get', 'update'])
+    check_call(['sudo', 'apt-get', 'install', 'python-virtualenv', 'nodejs'])
+    check_call(['sudo', 'npm', 'install', '-g', 'less@2.6.1', 'less-plugin-clean-css'])
+    deb_file = 'doxygen_1.8.6-2_amd64.deb'
+    urllib.urlretrieve('http://mirrors.kernel.org/ubuntu/pool/main/d/doxygen/' +
+                       deb_file, deb_file)
+    check_call(['sudo', 'dpkg', '-i', deb_file])
+
+fmt_dir = os.path.dirname(os.path.dirname(os.path.realpath(__file__)))
+
+build = os.environ['BUILD']
+if build == 'Doc':
+    travis = 'TRAVIS' in os.environ
+    if travis:
+        install_dependencies()
+    sys.path.insert(0, os.path.join(fmt_dir, 'doc'))
+    import build
+    build.create_build_env()
+    html_dir = build.build_docs()
+    repo = 'fmtlib.github.io'
+    if travis and 'KEY' not in os.environ:
+        # Don't update the repo if building on Travis from an account that
+        # doesn't have push access.
+        print('Skipping update of ' + repo)
+        exit(0)
+    # Clone the fmtlib.github.io repo.
+    rmtree_if_exists(repo)
+    git_url = 'https://github.com/' if travis else 'git@github.com:'
+    check_call(['git', 'clone', git_url + 'fmtlib/{}.git'.format(repo)])
+    # Copy docs to the repo.
+    target_dir = os.path.join(repo, 'dev')
+    rmtree_if_exists(target_dir)
+    shutil.copytree(html_dir, target_dir, ignore=shutil.ignore_patterns('.*'))
+    if travis:
+        check_call(['git', 'config', '--global', 'user.name', 'amplbot'])
+        check_call(['git', 'config', '--global', 'user.email', 'viz@ampl.com'])
+    # Push docs to GitHub pages.
+    check_call(['git', 'add', '--all'], cwd=repo)
+    if call(['git', 'diff-index', '--quiet', 'HEAD'], cwd=repo):
+        check_call(['git', 'commit', '-m', 'Update documentation'], cwd=repo)
+        cmd = 'git push'
+        if travis:
+            cmd += ' https://$KEY@github.com/fmtlib/fmtlib.github.io.git master'
+        p = Popen(cmd, shell=True, stdout=PIPE, stderr=STDOUT, cwd=repo)
+        # Print the output without the key.
+        print(p.communicate()[0].replace(os.environ['KEY'], '$KEY'))
+        if p.returncode != 0:
+            raise subprocess.CalledProcessError(p.returncode, cmd)
+    exit(0)
+
+standard = os.environ['STANDARD']
+install_dir    = os.path.join(fmt_dir, "_install")
+build_dir      = os.path.join(fmt_dir, "_build")
+test_build_dir = os.path.join(fmt_dir, "_build_test")
+
+# Configure library.
+makedirs_if_not_exist(build_dir)
+cmake_flags = [
+    '-DCMAKE_INSTALL_PREFIX=' + install_dir, '-DCMAKE_BUILD_TYPE=' + build,
+    '-DCMAKE_CXX_STANDARD=' + standard
+]
+check_call(['cmake', '-DFMT_DOC=OFF', '-DFMT_PEDANTIC=ON', '-DFMT_WERROR=ON', fmt_dir] +
+           cmake_flags, cwd=build_dir)
+
+# Build library.
+check_call(['make', '-j4'], cwd=build_dir)
+
+# Test library.
+env = os.environ.copy()
+env['CTEST_OUTPUT_ON_FAILURE'] = '1'
+if call(['make', 'test'], env=env, cwd=build_dir):
+    with open(os.path.join(build_dir, 'Testing', 'Temporary', 'LastTest.log'), 'r') as f:
+        print(f.read())
+    sys.exit(-1)
+
+# Install library.
+check_call(['make', 'install'], cwd=build_dir)
+
+# Test installation.
+makedirs_if_not_exist(test_build_dir)
+check_call(['cmake', os.path.join(fmt_dir, "test", "find-package-test")] +
+            cmake_flags, cwd=test_build_dir)
+check_call(['make', '-j4'], cwd=test_build_dir)