Add $(LIBM) to the LDADD for all of the examples and tests

Some of the examples and tests are using functions from -lm. With some
linkers, if we don't expicitly link against it an error will be
reported. This patch adds the library to all of the examples even
though not all of them use math functions because I don't think it
will do any harm and it will save us having to remember to add it if
an example later starts using some math functions.

https://bugzilla.gnome.org/show_bug.cgi?id=697330

Reviewed-by: Robert Bragg <robert@linux.intel.com>

(cherry picked from commit 66a1aeaee1f7cdcdd505f5745277723a43d714b6)

Conflicts:
	examples/Makefile.am
	tests/conform/Makefile.am
	tests/micro-perf/Makefile.am

examples/Makefile.am

@@ -20,7 +20,8 @@ endif
 
 common_ldadd = \
 	$(COGL_DEP_LIBS) \
-	$(top_builddir)/cogl/libcogl.la
+	$(top_builddir)/cogl/libcogl.la \
+	$(LIBM)
 
 if !USE_GLIB
 common_ldadd += $(top_builddir)/deps/glib/libglib.la

tests/conform/Makefile.am

@@ -132,7 +132,10 @@ AM_CPPFLAGS += \
 	-DCOGL_COMPILATION
 
 test_conformance_CFLAGS = -g3 -O0 $(COGL_DEP_CFLAGS) $(COGL_EXTRA_CFLAGS)
-test_conformance_LDADD = $(COGL_DEP_LIBS) $(top_builddir)/cogl/libcogl.la
+test_conformance_LDADD = \
+	$(COGL_DEP_LIBS) \
+	$(top_builddir)/cogl/libcogl.la \
+	$(LIBM)
 if !USE_GLIB
 test_conformance_LDADD += $(top_builddir)/deps/glib/libglib.la
 endif

tests/micro-perf/Makefile.am

@@ -19,5 +19,10 @@ endif
 
 AM_CFLAGS = $(COGL_DEP_CFLAGS) $(COGL_EXTRA_CFLAGS)
 
+common_ldadd = \
+	$(COGL_DEP_LIBS) \
+	$(top_builddir)/cogl/libcogl.la \
+	$(LIBM)
+
 test_journal_SOURCES = test-journal.c
-test_journal_LDADD = $(COGL_DEP_LIBS) $(top_builddir)/cogl/libcogl.la
+test_journal_LDADD = $(common_ldadd)