[gimp] plug-ins: link dds plugins against libm

[Øyvind "pippin" Kolås <ok src gnome org>]

commit 1661aab620d9fc25cccca31ef1b8012b87655fc1
Author: Øyvind Kolås <pippin gimp org>
Date:   Sun Aug 4 14:21:46 2019 +0200

    plug-ins: link dds plugins against libm

 plug-ins/file-dds/Makefile.am | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/plug-ins/file-dds/Makefile.am b/plug-ins/file-dds/Makefile.am
index b62d822fbc..72fc5a7c0a 100644
--- a/plug-ins/file-dds/Makefile.am
+++ b/plug-ins/file-dds/Makefile.am
@@ -10,6 +10,8 @@ libgimpmath = $(top_builddir)/libgimpmath/libgimpmath-$(GIMP_API_VERSION).la
 
 if OS_WIN32
 mwindows = -mwindows
+else
+libm     = -lm
 endif
 
 if HAVE_WINDRES
@@ -58,6 +60,7 @@ LDADD = \
        $(libgimpcolor)         \
        $(libgimpmath)          \
        $(libgimpbase)          \
+       $(libm)                 \
        $(GTK_LIBS)             \
        $(GEGL_LIBS)            \
        $(RT_LIBS)              \