Allow command lists for find_program cross file overrides

This is accepted by all other binaries in the cross file. With this
change, we also don't check whether the specified command exists at
configure time, but that's probably a feature anyway.

Fixes https://github.com/mesonbuild/meson/issues/3737

mesonbuild/interpreter.py

@@ -2627,8 +2627,12 @@ external dependencies (including libraries) must go to "dependencies".''')
             if not isinstance(p, str):
                 raise InterpreterException('Executable name must be a string.')
             if p in bins:
-                exename = bins[p]
-                extprog = dependencies.ExternalProgram(exename, silent=silent)
+                command = bins[p]
+                if isinstance(command, (list, str)):
+                    extprog = dependencies.ExternalProgram(p, command=command, silent=silent)
+                else:
+                    raise InterpreterException('Invalid type {!r} for binary {!r} in cross file'
+                                               ''.format(command, p))
                 progobj = ExternalProgramHolder(extprog)
                 return progobj
 

run_unittests.py

@@ -3207,7 +3207,8 @@ class LinuxlikeTests(BasePlatformTests):
 c = '/usr/bin/cc'
 ar = '/usr/bin/ar'
 strip = '/usr/bin/ar'
-sometool.py = '%s'
+sometool.py = ['{0}']
+someothertool.py = '{0}'
 
 [properties]
 
@@ -3216,7 +3217,7 @@ system = 'linux'
 cpu_family = 'arm'
 cpu = 'armv7' # Not sure if correct.
 endian = 'little'
-''' % os.path.join(testdir, 'some_cross_tool.py'))
+'''.format(os.path.join(testdir, 'some_cross_tool.py')))
         crossfile.flush()
         self.meson_cross_file = crossfile.name
         self.init(testdir)

test cases/unit/12 cross prog/meson.build

@@ -2,11 +2,15 @@ project('cross find program', 'c')
 
 native_exe = find_program('sometool.py', native : true)
 cross_exe = find_program('sometool.py')
+cross_other_exe = find_program('someothertool.py')
 
 native_out = run_command(native_exe).stdout().strip()
 cross_out = run_command(cross_exe).stdout().strip()
+cross_other_out = run_command(cross_other_exe).stdout().strip()
 
 assert(native_out == 'native',
   'Native output incorrect:' + native_out)
 assert(cross_out == 'cross',
   'Cross output incorrect:' + cross_out)
+assert(cross_out == cross_other_out,
+  'Cross output incorrect:' + cross_other_out)