Makefile.am: drop unneeded '-ldl -pthread' from AM_CXXFLAGS

Change-Id: I833864aa51059be9c97c16329bc16913c53e171d
diff --git a/src/Makefile.am b/src/Makefile.am
index dea4a17..f338624 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -33,7 +33,7 @@
 AM_CPPFLAGS += -DENABLE_DIRECT_PHY
 endif
 
-AM_CXXFLAGS = -Wall -ldl -pthread
+AM_CXXFLAGS = -Wall
 AM_LDFLAGS = -lrt
 
 noinst_LTLIBRARIES = libgprs.la