package/trace-cmd: fix build for Sparc64

Trace-cmd needs -fPIC for Sparc64 platform otherwise it fails on linking,
so add -fPIC to CFLAGS when building for such platform.

Fixes;
    http://autobuild.buildroot.net/results/c59/c596f6308b7f4d44d9ba009ed0c395396fc72f47/

Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
(cherry picked from commit b1942c8e47d0898ee0598a57626d3dae868782e1)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/trace-cmd/trace-cmd.mk

@@ -31,6 +31,11 @@ endif
 # redefining it on the command line causes build problems.
 TRACE_CMD_CFLAGS = $(filter-out -D_LARGEFILE64_SOURCE,$(TARGET_CFLAGS))
 
+# Sparc64 needs -fPIC
+ifeq ($(BR2_sparc64),y)
+TRACE_CMD_CFLAGS += -fPIC
+endif
+
 # trace-cmd use CPPFLAGS to add some extra flags.
 # But like for CFLAGS, $(TARGET_CPPFLAGS) contains _LARGEFILE64_SOURCE
 # that causes build problems.