cmake: Detect custom command targets in compiler args

This is required to make `-include /path/to/custom/target.hpp`
work. This setup is used by wxWidgets and this PR is
required to use wxWidgets as a CMake subproject.

mesonbuild/cmake/interpreter.py

@@ -279,7 +279,7 @@ class ConverterTarget:
     std_regex = re.compile(r'([-]{1,2}std=|/std:v?|[-]{1,2}std:)(.*)')
 
     def postprocess(self, output_target_map: OutputTargetMap, root_src_dir: str, subdir: str, install_prefix: str, trace: CMakeTraceParser) -> None:
-        # Detect setting the C and C++ standard
+        # Detect setting the C and C++ standard and do additional compiler args manipulation
         for i in ['c', 'cpp']:
             if i not in self.compile_opts:
                 continue
@@ -287,6 +287,7 @@ class ConverterTarget:
             temp = []
             for j in self.compile_opts[i]:
                 m = ConverterTarget.std_regex.match(j)
+                ctgt = output_target_map.generated(j)
                 if m:
                     std = m.group(2)
                     supported = self._all_lang_stds(i)
@@ -301,6 +302,12 @@ class ConverterTarget:
                     self.override_options += ['{}_std={}'.format(i, std)]
                 elif j in ['-fPIC', '-fpic', '-fPIE', '-fpie']:
                     self.pie = True
+                elif isinstance(ctgt, ConverterCustomTarget):
+                    # Sometimes projects pass generated source files as compiler
+                    # flags. Add these as generated sources to ensure that the
+                    # corresponding custom target is run.2
+                    self.generated += [j]
+                    temp += [j]
                 elif j in blacklist_compiler_flags:
                     pass
                 else:

test cases/cmake/8 custom command/subprojects/cmMod/CMakeLists.txt

@@ -134,6 +134,16 @@ add_custom_target(args_test_cmd
 )
 add_custom_target(macro_name_cmd COMMAND macro_name)
 
+if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
+  message(STATUS "Running the -include test case on macro_name")
+  add_custom_command(
+    OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/cpyInc.hpp"
+    COMMAND mycpy "${CMAKE_CURRENT_SOURCE_DIR}/cpyInc.hpp.am" "${CMAKE_CURRENT_BINARY_DIR}/cpyInc.hpp"
+    DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/cpyInc.hpp.am"
+  )
+  target_compile_options(macro_name PUBLIC -DTEST_CMD_INCLUDE -include "${CMAKE_CURRENT_BINARY_DIR}/cpyInc.hpp")
+endif()
+
 # Only executable targets are replaced in the command
 # all other target names are kept as is
 add_custom_target(clang-format COMMAND clang-format -i cmMod.cpp)

test cases/cmake/8 custom command/subprojects/cmMod/cpyInc.hpp.am

@@ -0,0 +1,3 @@
+#pragma once
+
+#define CPY_INC_WAS_INCLUDED 1

test cases/cmake/8 custom command/subprojects/cmMod/macro_name.cpp

@@ -5,6 +5,12 @@
 
 using namespace std;
 
+#ifdef TEST_CMD_INCLUDE
+#if CPY_INC_WAS_INCLUDED != 1
+#error "cpyInc.hpp was not included"
+#endif
+#endif
+
 int main() {
   this_thread::sleep_for(chrono::seconds(1));
   ofstream out1("macro_name.txt");