Fix Solaris linking.

Need to file an upstream bug

--- pygobject-3.16.1/configure.ac	2015-04-13 19:39:58.000000000 -0700
+++ pygobject-3.16.1/configure.ac	2015-06-04 13:06:43.904168525 -0700
@@ -51,7 +51,7 @@
 
 AC_CANONICAL_BUILD
 AC_CANONICAL_HOST
-AC_MSG_CHECKING([for build time linking with Python (Darwin and Win32)])
+AC_MSG_CHECKING([for build time linking with Python (Darwin, Solaris, and Win32)])
 case "$host" in
   *-*-mingw*|*-*-cygwin*)
     os_win32=yes
@@ -63,6 +63,12 @@
     link_python_libs=yes
     OS_EXT=dylib
     ;;
+  *solaris*)
+    dnl Required due to -no-undefined linking.
+    os_win32=no
+    link_python_libs=yes
+    OS_EXT=so
+    ;;
   *)
     os_win32=no
     link_python_libs=no