[gobject-introspection] customize_compiler: also replace the linker command if CC is set

[Christoph Reiter <creiter src gnome org>]

commit d1e234ec171e9f60bd54837071ef60ca7b0568c7
Author: Christoph Reiter <reiter christoph gmail com>
Date:   Sat Dec 29 19:42:08 2018 +0100

    customize_compiler: also replace the linker command if CC is set
    
    Otherwise when you set CC=clang then distuils will still use gcc for linking.
    While it seems we don't invoke the link command atm this shouldn't hurt.
    
    The upstream customize_compiler() does the same thing on macOS and there is a bug
    for enabling it everywhere: https://bugs.python.org/issue24935

 giscanner/ccompiler.py          | 5 ++++-
 tests/scanner/test_ccompiler.py | 5 +++++
 2 files changed, 9 insertions(+), 1 deletion(-)
---
diff --git a/giscanner/ccompiler.py b/giscanner/ccompiler.py
index 8ea99445..aee6a1af 100644
--- a/giscanner/ccompiler.py
+++ b/giscanner/ccompiler.py
@@ -45,7 +45,10 @@ def customize_compiler(compiler):
             get_config_vars('CC', 'CXX', 'LDSHARED', 'SHLIB_SUFFIX', 'AR', 'ARFLAGS')
 
         if 'CC' in os.environ:
-            cc = os.environ['CC']
+            newcc = os.environ['CC']
+            if 'LDSHARED' not in os.environ and ldshared.startswith(cc):
+                ldshared = newcc + ldshared[len(cc):]
+            cc = newcc
         if 'CXX' in os.environ:
             cxx = os.environ['CXX']
         if 'LDSHARED' in os.environ:
diff --git a/tests/scanner/test_ccompiler.py b/tests/scanner/test_ccompiler.py
index ac50e245..dd8700d8 100644
--- a/tests/scanner/test_ccompiler.py
+++ b/tests/scanner/test_ccompiler.py
@@ -62,6 +62,11 @@ class UnixCCompilerTest(unittest.TestCase):
             except ValueError:
                 self.fail('%r is not a subsequence of %r' % (list1, list2))
 
+    def test_link_args_override(self):
+        with Environ(dict(CC="foobar")):
+            compiler = CCompiler()
+            self.assertEqual(compiler.compiler.linker_so[0], "foobar")
+
     def compile_args(self, environ={}, compiler_name='unix',
                      pkg_config_cflags=[], cpp_includes=[],
                      source='a.c', init_sections=[]):