Preserve the order of internal deps in a target

We were adding them to the CompilerArgs instance in the order in which
they are specified, which is wrong because later dependencies would
override previous ones. Add them in the reverse order instead.

Closes https://github.com/mesonbuild/meson/issues/1495

1 files changed, 5 insertions, 3 deletions

diff --git a/mesonbuild/backend/backends.py b/mesonbuild/backend/backends.py
index 5939488..fa9a82f 100644
--- a/mesonbuild/backend/backends.py
+++ b/mesonbuild/backend/backends.py
@@ -375,9 +375,11 @@ class Backend:
         # Set -fPIC for static libraries by default unless explicitly disabled
         if isinstance(target, build.StaticLibrary) and target.pic:
             commands += compiler.get_pic_args()
-        # Add compile args needed to find external dependencies
-        # Link args are added while generating the link command
-        for dep in target.get_external_deps():
+        # Add compile args needed to find external dependencies. Link args are
+        # added while generating the link command.
+        # NOTE: We must preserve the order in which external deps are
+        # specified, so we reverse the list before iterating over it.
+        for dep in reversed(target.get_external_deps()):
             commands += dep.get_compile_args()
             # Qt needs -fPIC for executables
             # XXX: We should move to -fPIC for all executables