1 files changed, 21 insertions, 0 deletions
diff --git a/mesonbuild/backend/backends.py b/mesonbuild/backend/backends.py
index 4139ace..5681f7c 100644
--- a/mesonbuild/backend/backends.py
+++ b/mesonbuild/backend/backends.py
@@ -630,3 +630,24 @@ class Backend():
         for s in self.build.postconf_scripts:
             cmd = s['exe'].get_command() + s['args']
             subprocess.check_call(cmd, env=child_env)
+
+    # Subprojects of subprojects may cause the same dep args to be used
+    # multiple times. Remove duplicates here. Note that we can't dedup
+    # libraries based on name alone, because "-lfoo -lbar -lfoo" is 
+    # a completely valid (though pathological) sequence and removing the
+    # latter may fail. Usually only applies to static libs, though.
+    def dedup_arguments(self, commands):
+        includes = {}
+        final_commands = []
+        previous = '-fsuch_arguments=woof'
+        for c in commands:
+            if c.startswith(('-I' '-L', '/LIBPATH')):
+                if c in includes:
+                    continue
+                includes[c] = True
+            if previous == c:
+                continue
+            previous = c
+            final_commands.append(c)
+        return final_commands
+