linkers: reorganize Ar linker into a base class

The `init__()` method basically existed solely to be overridden by every
derivative class. Better to use it only in the class that needs it.

This fixes several warnings, including missing calls to init because we
skipped ArLinker due to not wanting it... also get rid of a pointless
popen return code saved as pc, which we never checked.

mesonbuild/linkers/linkers.py

@@ -167,21 +167,14 @@ class IntelVisualStudioLinker(VisualStudioLikeLinker, StaticLinker):
         VisualStudioLikeLinker.__init__(self, machine)
 
 
-class ArLinker(StaticLinker):
-
-    def __init__(self, exelist: T.List[str]):
-        super().__init__(exelist)
-        self.id = 'ar'
-        pc, stdo = mesonlib.Popen_safe(self.exelist + ['-h'])[0:2]
-        # Enable deterministic builds if they are available.
-        if '[D]' in stdo:
-            self.std_args = ['csrD']
-        else:
-            self.std_args = ['csr']
-        self.can_rsp = '@<' in stdo
+class ArLikeLinker(StaticLinker):
+    # POSIX requires supporting the dash, GNU permits omitting it
+    std_args = ['-csr']
 
     def can_linker_accept_rsp(self) -> bool:
-        return self.can_rsp
+        # armar / AIX can't accept arguments using the @rsp syntax
+        # in fact, only the 'ar' id can
+        return False
 
     def get_std_link_args(self) -> T.List[str]:
         return self.std_args
@@ -193,16 +186,25 @@ class ArLinker(StaticLinker):
         return RSPFileSyntax.GCC
 
 
-class ArmarLinker(ArLinker):  # lgtm [py/missing-call-to-init]
+class ArLinker(ArLikeLinker):
+    id = 'ar'
 
     def __init__(self, exelist: T.List[str]):
-        StaticLinker.__init__(self, exelist)
-        self.id = 'armar'
-        self.std_args = ['-csr']
+        super().__init__(exelist)
+        stdo = mesonlib.Popen_safe(self.exelist + ['-h'])[1]
+        # Enable deterministic builds if they are available.
+        if '[D]' in stdo:
+            self.std_args = ['csrD']
+        else:
+            self.std_args = ['csrD']
+        self.can_rsp = '@<' in stdo
 
     def can_linker_accept_rsp(self) -> bool:
-        # armar can't accept arguments using the @rsp syntax
-        return False
+        return self.can_rsp
+
+
+class ArmarLinker(ArLikeLinker):  # lgtm [py/missing-call-to-init]
+    id = 'armar'
 
 
 class DLinker(StaticLinker):
@@ -291,16 +293,9 @@ class C2000Linker(StaticLinker):
         return ['-r']
 
 
-class AIXArLinker(ArLinker):
-
-    def __init__(self, exelist: T.List[str]):
-        StaticLinker.__init__(self, exelist)
-        self.id = 'aixar'
-        self.std_args = ['-csr', '-Xany']
-
-    def can_linker_accept_rsp(self) -> bool:
-        # AIXAr can't accept arguments using the @rsp syntax
-        return False
+class AIXArLinker(ArLikeLinker):
+    id = 'aixar'
+    std_args = ['-csr', '-Xany']
 
 
 def prepare_rpaths(raw_rpaths: str, build_dir: str, from_dir: str) -> T.List[str]: