setup.py: Provide instructions to install cmake

If cmake_path is not found, either cmake is not installed
or cmake is not in the PATH. Hence, we also give instructions
on how to install cmake if the path is not found.

setup.py

@@ -456,7 +456,42 @@ class build(_build):
         """use cmake to build and install the extension
         """
         if cmake_path is None:
-            raise DistutilsSetupError("Cannot find cmake in the path. Please specify its path with --cmake parameter.")
+            cmake_install_url = "https://cmake.org/install/"
+            message = ("You can install cmake using the instructions at " +
+                       cmake_install_url)
+            msg_pkgmanager = ("You can install cmake on {0} using "
+                              "`sudo {1} install cmake`.")
+            if sys.platform == "darwin":
+                pkgmanagers = ('brew', 'port')
+                for manager in pkgmanagers:
+                    if find_executable(manager) is not None:
+                        message = msg_pkgmanager.format('OSX', manager)
+                        break
+            elif sys.platform.startswith('linux'):
+                distname = None
+                try:
+                    import distro
+                except ImportError:
+                    import pip
+                    pip_exit = pip.main(['install', 'distro'])
+                    if pip_exit > 0:
+                        raise SystemExit('Pip was unable to install `distro`')
+                    import distro
+                distname = distro.id()
+                if distname in ('debian', 'ubuntu'):
+                    message = msg_pkgmanager.format(
+                        distname.title(), 'apt-get')
+                elif distname in ('fedora', 'centos', 'redhat'):
+                    pkgmanagers = ("dnf", "yum")
+                    for manager in pkgmanagers:
+                        if find_executable(manager) is not None:
+                            message = msg_pkgmanager.format(
+                                distname.title(), manager)
+                            break
+            raise DistutilsSetupError(
+                "Cannot find cmake, ensure it is installed and in the path.\n"
+                + message + "\n"
+                "You can also specify its path with --cmake parameter.")
 
         platform_arch = platform.architecture()[0]
         log.info("Detected Python architecture: %s" % platform_arch)