setupext: respect $PKG_CONFIG

When cross-compiling, it is common to set the PKG_CONFIG env var to a custom pkg-config that knows about the target. Make sure we respect that just like the standard pkg-config tools suggest (pkg.m4). If it isn't set, we use the same default as today -- "pkg-config".
matplotlib · vapier · May 15, 2015 · May 15, 2015 · May 15, 2015 · May 15, 2015
commit 08d26a80859023963bc2ffb41a0b6aed942685a9
diff --git a/setupext.py b/setupext.py
@@ -253,7 +253,8 @@ def __init__(self):
            self.has_pkgconfig = False
        else:
            self.set_pkgconfig_path()
-            status, output = getstatusoutput("pkg-config --help")
+            self.pkgconfig = os.environ.get('PKG_CONFIG', 'pkg-config')
+            status, output = getstatusoutput("%s --help" % self.pkgconfig)
            self.has_pkgconfig = (status == 0)
            if not self.has_pkgconfig:
                print("IMPORTANT WARNING:")
@@ -286,7 +287,7 @@ def setup_extension(self, ext, package, default_include_dirs=[],

        executable = alt_exec
        if self.has_pkgconfig:
-            executable = 'pkg-config {0}'.format(package)
+            executable = '%s %s' % (self.pkgconfig, package)

        use_defaults = True

@@ -330,7 +331,7 @@ def get_version(self, package):
            return None

        status, output = getstatusoutput(
-            "pkg-config %s --modversion" % (package))
+            '%s %s --modversion' % (self.pkgconfig, package))
        if status == 0:
            return output
        return None