pkgconfig: set libdir only if used
This should address some concerns outlined in
@@ -347,6 +347,7 @@ class PkgConfigModule(ExtensionModule):
ofile.write('prefix={}\n'.format(self._escape(prefix)))
if uninstalled:
ofile.write('srcdir={}\n'.format(self._escape(srcdir)))
+ if deps.pub_libs or deps.priv_libs:
ofile.write('libdir={}\n'.format(self._escape('${prefix}' / libdir)))
ofile.write('includedir={}\n'.format(self._escape('${prefix}' / incdir)))
if variables or unescaped_variables:
