Revert "Rename objective-c files from .c to .m"

This reverts commit e400af99d4.

gio/Makefile.am

@@ -602,25 +602,10 @@ libgio_2_0_la_LDFLAGS = $(GLIB_LINK_FLAGS) \
 	-export-dynamic $(no_undefined)
 
 if OS_COCOA
-# We cannot build .m files because it would require adding AC_PROG_OBJC in
-# configure.ac, and it cannot be added conditionally. That means we would always
-# depend on an objective-c compiler even when not needed. To work around that
-# limitation we rename .m files to .c and compile them separately with
-# -xobjective-c into an intermediary library. Note that we cannot rename those
-# files to .c directly in the source tree because Meson needs the .m extension.
-# See https://bugzilla.gnome.org/show_bug.cgi?id=672777.
-OBJC_FILES = \
-	gnextstepsettingsbackend.m \
-	gosxcontenttype.m \
-	gosxappinfo.m \
-	gcocoanotificationbackend.m \
-	$(NULL)
-OBJC_C_FILES = $(OBJC_FILES:.m=.c)
-BUILT_SOURCES += $(OBJC_C_FILES)
-CLEANFILES += $(OBJC_C_FILES)
-$(OBJC_C_FILES): %.c: %.m Makefile
-	cp $< $@
-
+# Let's avoid polluting the CFLAGS of libgio with -xobjective-c
+# We cannot simply rename the ObjC files to .m because it plays
+# tricks with Automake. For further reference, see:
+# https://bugzilla.gnome.org/show_bug.cgi?id=672777
 libgio_objc_2_0_la_CFLAGS = $(libgio_2_0_la_CFLAGS) -xobjective-c
 libgio_objc_2_0_la_CPPFLAGS = $(libgio_2_0_la_CPPFLAGS)
 libgio_objc_2_0_la_LDFLAGS = $(libgio_2_0_la_LDFLAGS) -Wl,-framework,Foundation -Wl,-framework,AppKit

gio/meson.build

@@ -292,6 +292,11 @@ if host_system == 'windows'
   settings_sources += files('gregistrysettingsbackend.c')
 endif
 
+# FIXME:
+#if OS_COCOA
+#settings_sources += files('gnextstepsettingsbackend.c')
+#endif
+
 application_headers = files(
   'gapplication.h',
   'gapplicationcommandline.h',
@@ -407,11 +412,10 @@ if host_system != 'windows'
   )
 
   if glib_have_cocoa
-    settings_sources += files('gnextstepsettingsbackend.m')
-    contenttype_sources += files('gosxcontenttype.m')
-    appinfo_sources += files('gosxappinfo.m')
+    contenttype_sources += files('gosxcontenttype.c')
+    appinfo_sources += files('gosxappinfo.c')
     if glib_have_os_x_9_or_later
-      unix_sources += files('gcocoanotificationbackend.m')
+      unix_sources += files('gcocoanotificationbackend.c')
     endif
   else
     contenttype_sources += files('gcontenttype.c')