[gegl] tests: add math lib in buffer tests

[Øyvind Kolås <ok src gnome org>]

commit 002cd18bf2e93f71e5dbba1f4ad33ffd43d52e75
Author: Tim Lunn <tim feathertop org>
Date:   Tue Mar 31 08:45:26 2015 +1100

    tests: add math lib in buffer tests
    
    This fixes a DSO Linker error that occurs when built with --as-needed

 tests/buffer/Makefile.am |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/tests/buffer/Makefile.am b/tests/buffer/Makefile.am
index 686f552..41cb211 100644
--- a/tests/buffer/Makefile.am
+++ b/tests/buffer/Makefile.am
@@ -34,7 +34,7 @@ buffer_test_SOURCES_noinc = buffer-test.c
 buffer_test_SOURCES = $(buffer_test_SOURCES_noinc) buffer-tests.inc
 buffer_test_LDADD =                                            \
        $(top_builddir)/gegl/libgegl-$(GEGL_API_VERSION).la     \
-       $(DEP_LIBS) $(BABL_LIBS)
+       $(DEP_LIBS) $(BABL_LIBS) $(MATH_LIB)
 
 
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