guile: use libltdl, needs dynamic libraries

Fixes:
http://autobuild.buildroot.net/results/8d0/8d0e8ab0e7a83fda9ee65f973b5b749b246f1c1a/
http://autobuild.buildroot.net/results/381/38137ccf29023f38c540483a6655c4b8d6778abd/
http://autobuild.buildroot.net/results/1d8/1d864588f71b8c13a67781cf91ad058c74eb7abc/

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/guile/Config.in

@@ -3,6 +3,7 @@ config BR2_PACKAGE_GUILE
 	depends on BR2_TOOLCHAIN_HAS_THREADS
 	depends on BR2_PACKAGE_LIBATOMIC_ARCH_SUPPORTS # bdwgc
 	depends on BR2_USE_WCHAR # libunistring
+	depends on !BR2_STATIC_LIBS
 	select BR2_PACKAGE_LIBUNISTRING
 	select BR2_PACKAGE_LIBFFI
 	select BR2_PACKAGE_GMP
@@ -14,6 +15,7 @@ config BR2_PACKAGE_GUILE
 
 	  http://www.gnu.org/software/guile
 
-comment "guile needs a toolchain w/ threads, wchar"
-	depends on !BR2_TOOLCHAIN_HAS_THREADS || !BR2_USE_WCHAR
+comment "guile needs a toolchain w/ threads, wchar, dynamic library"
+	depends on !BR2_TOOLCHAIN_HAS_THREADS || !BR2_USE_WCHAR || \
+		BR2_STATIC_LIBS