[gegl] build: Link against -lm, where necessary

[Debarshi Ray <debarshir src gnome org>]

commit ff32ed4d7bbf2acb56a17e8b467ac72b6c8ce4a5
Author: Debarshi Ray <debarshir gnome org>
Date:   Fri Jan 26 12:10:40 2018 +0100

    build: Link against -lm, where necessary

 libs/npd/Makefile.am |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/libs/npd/Makefile.am b/libs/npd/Makefile.am
index 4215515..f2bba45 100644
--- a/libs/npd/Makefile.am
+++ b/libs/npd/Makefile.am
@@ -39,4 +39,4 @@ libgegl_npd_@GEGL_API_VERSION@_la_CFLAGS = \
 lib_LTLIBRARIES = libgegl-npd-@GEGL_API_VERSION@.la
 
 libgegl_npd_@GEGL_API_VERSION@_la_LIBADD = \
-       $(libgegl) $(GLIB_LIBS) $(BABL_LIBS)
+       $(libgegl) $(GLIB_LIBS) $(BABL_LIBS) $(MATH_LIB)