objc++: Add support for objcpp_args keyword

This allows the user to pass additional flags for the objective-c++
compiler.

mesonbuild/build.py

@@ -29,6 +29,7 @@ known_basic_kwargs = {'install': True,
                       'cpp_pch': True,
                       'c_args': True,
                       'objc_args': True,
+                      'objcpp_args': True,
                       'cpp_args': True,
                       'cs_args': True,
                       'vala_args': True,
@@ -632,6 +633,10 @@ class BuildTarget(Target):
         if not isinstance(objclist, list):
           objclist = [objclist]
         self.add_compiler_args('objc', objclist)
+        objcpplist = kwargs.get('objcpp_args', [])
+        if not isinstance(objcpplist, list):
+          objcpplist = [objcpplist]
+        self.add_compiler_args('objcpp', objcpplist)
         fortranlist = kwargs.get('fortran_args', [])
         if not isinstance(fortranlist, list):
             fortranlist = [fortranlist]

test cases/objc/5 objc++ args/meson.build

@@ -0,0 +1,4 @@
+project('objective c++ args', 'objcpp')
+
+exe = executable('prog', 'prog.mm', objcpp_args : ['-DMESON_OBJCPP_TEST'])
+test('objective c++ args', exe)

test cases/objc/5 objc++ args/prog.mm

@@ -0,0 +1,16 @@
+#import<stdio.h>
+
+class TestClass
+{
+};
+
+int main(int argc, char **argv)
+{
+#ifdef MESON_OBJCPP_TEST
+int x = 1;
+#endif
+
+  printf("x = %x\n", x);
+
+  return 0;
+}