Execute python scripts with the same interpreter

This reads the python interpreter’s path and executes any other scripts
using the same interpreter. This way, mbed CLI is guaranteed to execute
subscripts in `python2`, rather than the system default `python`.

Author: bremoran

mbed/mbed.py

@@ -42,6 +42,7 @@
 # Default paths to Mercurial and Git
 hg_cmd = 'hg'
 git_cmd = 'git'
+python_cmd = sys.executable
 
 ignores = [
     # Version control folders
@@ -2175,7 +2176,7 @@ def compile_(toolchain=None, target=None, profile=False, compile_library=False,
         source = [os.path.relpath(program.path, orig_path)]
 
     if supported:
-        popen(['python2', '-u', os.path.join(tools_dir, 'make.py')]
+        popen([python_cmd, '-u', os.path.join(tools_dir, 'make.py')]
               + (['-S'] if supported else []) + (['-v'] if very_verbose else [])
               + (['--app-config', app_config] if app_config else [])
               + args,
@@ -2188,7 +2189,7 @@ def compile_(toolchain=None, target=None, profile=False, compile_library=False,
 
     if compile_config:
         # Compile configuration
-        popen(['python2', os.path.join(tools_dir, 'get_config.py')]
+        popen([python_cmd, os.path.join(tools_dir, 'get_config.py')]
               + ['-t', tchain, '-m', target]
               + list(chain.from_iterable(izip(repeat('--profile'), profile or [])))
               + list(chain.from_iterable(izip(repeat('--source'), source)))
@@ -2207,7 +2208,7 @@ def compile_(toolchain=None, target=None, profile=False, compile_library=False,
             if not build_path:
                 build_path = os.path.join(os.path.relpath(program.path, orig_path), program.build_dir, 'libraries', os.path.basename(orig_path), target, tchain)
 
-            popen(['python2', '-u', os.path.join(tools_dir, 'build.py')]
+            popen([python_cmd, '-u', os.path.join(tools_dir, 'build.py')]
                   + list(chain.from_iterable(izip(repeat('-D'), macros)))
                   + ['-t', tchain, '-m', target]
                   + list(chain.from_iterable(izip(repeat('--profile'), profile or [])))
@@ -2223,7 +2224,7 @@ def compile_(toolchain=None, target=None, profile=False, compile_library=False,
             if not build_path:
                 build_path = os.path.join(os.path.relpath(program.path, orig_path), program.build_dir, target, tchain)
 
-            popen(['python2', '-u', os.path.join(tools_dir, 'make.py')]
+            popen([python_cmd, '-u', os.path.join(tools_dir, 'make.py')]
                   + list(chain.from_iterable(izip(repeat('-D'), macros)))
                   + ['-t', tchain, '-m', target]
                   + list(chain.from_iterable(izip(repeat('--profile'), profile or [])))
@@ -2292,7 +2293,7 @@ def test_(toolchain=None, target=None, compile_list=False, run_list=False, compi
             test_spec = os.path.join(build_path, 'test_spec.json')
 
         if compile_list:
-            popen(['python2', '-u', os.path.join(tools_dir, 'test.py'), '--list']
+            popen([python_cmd, '-u', os.path.join(tools_dir, 'test.py'), '--list']
                   + list(chain.from_iterable(izip(repeat('--profile'), profile or [])))
                   + ['-t', tchain, '-m', target]
                   + list(chain.from_iterable(izip(repeat('--source'), source)))
@@ -2307,7 +2308,7 @@ def test_(toolchain=None, target=None, compile_list=False, run_list=False, compi
             if not build:
                 program.ignore_build_dir()
 
-            popen(['python2', '-u', os.path.join(tools_dir, 'test.py')]
+            popen([python_cmd, '-u', os.path.join(tools_dir, 'test.py')]
                   + list(chain.from_iterable(izip(repeat('-D'), macros)))
                   + list(chain.from_iterable(izip(repeat('--profile'), profile or [])))
                   + ['-t', tchain, '-m', target]
@@ -2364,7 +2365,7 @@ def export(ide=None, target=None, source=False, clean=False, supported=False):
     env = program.get_env()
 
     if supported:
-        popen(['python2', '-u', os.path.join(tools_dir, 'project.py')]
+        popen([python_cmd, '-u', os.path.join(tools_dir, 'project.py')]
               + (['-S'] if supported else []) + (['-v'] if very_verbose else []),
               env=env)
         return
@@ -2380,7 +2381,7 @@ def export(ide=None, target=None, source=False, clean=False, supported=False):
 
     program.ignore_build_dir()
 
-    popen(['python2', '-u', os.path.join(tools_dir, 'project.py')]
+    popen([python_cmd, '-u', os.path.join(tools_dir, 'project.py')]
           + list(chain.from_iterable(izip(repeat('-D'), macros)))
           + ['-i', ide.lower()]
           + ['-m', target]
@@ -2412,7 +2413,7 @@ def detect():
         # Prepare environment variables
         env = program.get_env()
 
-        popen(['python2', '-u', os.path.join(tools_dir, 'detect_targets.py')]
+        popen([python_cmd, '-u', os.path.join(tools_dir, 'detect_targets.py')]
               + args,
               env=env)
     else: