backends: Treat build target as generator only when it's the first arg

Otherwise it might be an argument to a script that just inspects the
binary itself.

Author: nirbheek

mesonbuild/backend/backends.py

@@ -919,9 +919,9 @@ def check_clock_skew(self, file_list):
             if delta > 0.001:
                 raise MesonException('Clock skew detected. File {} has a time stamp {:.4f}s in the future.'.format(absf, delta))
 
-    def build_target_to_cmd_array(self, bt):
+    def build_target_to_cmd_array(self, bt, check_cross):
         if isinstance(bt, build.BuildTarget):
-            if isinstance(bt, build.Executable) and bt.for_machine is not MachineChoice.BUILD:
+            if check_cross and isinstance(bt, build.Executable) and bt.for_machine is not MachineChoice.BUILD:
                 if (self.environment.is_cross_build() and
                         self.environment.exe_wrapper is None and
                         self.environment.need_exe_wrapper()):
@@ -1061,9 +1061,11 @@ def eval_custom_target_command(self, target, absolute_outputs=False):
         inputs = self.get_custom_target_sources(target)
         # Evaluate the command list
         cmd = []
+        index = -1
         for i in target.command:
+            index += 1
             if isinstance(i, build.BuildTarget):
-                cmd += self.build_target_to_cmd_array(i)
+                cmd += self.build_target_to_cmd_array(i, (index == 0))
                 continue
             elif isinstance(i, build.CustomTarget):
                 # GIR scanner will attempt to execute this binary but

mesonbuild/backend/ninjabackend.py

@@ -1977,7 +1977,7 @@ def generate_genlist_for_target(self, genlist, target):
         generator = genlist.get_generator()
         subdir = genlist.subdir
         exe = generator.get_exe()
-        exe_arr = self.build_target_to_cmd_array(exe)
+        exe_arr = self.build_target_to_cmd_array(exe, True)
         infilelist = genlist.get_inputs()
         outfilelist = genlist.get_outputs()
         extra_dependencies = self.get_custom_target_depend_files(genlist)

mesonbuild/backend/vs2010backend.py

@@ -121,7 +121,7 @@ def generate_custom_generator_commands(self, target, parent_node):
                 infilelist = genlist.get_inputs()
                 outfilelist = genlist.get_outputs()
                 source_dir = os.path.join(down, self.build_to_src, genlist.subdir)
-                exe_arr = self.build_target_to_cmd_array(exe)
+                exe_arr = self.build_target_to_cmd_array(exe, True)
                 idgroup = ET.SubElement(parent_node, 'ItemGroup')
                 for i in range(len(infilelist)):
                     if len(infilelist) == len(outfilelist):