improve the makefile to support

[vipinpv85]

in order to have external dependencies for libraries and PMD and support latest DPDK, my suggestion is to update makefile

diff --git a/dpdk-apps/Makefile b/dpdk-apps/Makefile
index 3da318d..40a1e2f 100644
--- a/dpdk-apps/Makefile
+++ b/dpdk-apps/Makefile
@@ -31,7 +31,14 @@ include $(R2P2LIB_DIR)/dir.mk


 CC=gcc
-CFLAGS += -g -O3 -I$(ROOTDIR)/netstack/inc -I$(R2P2LIB_DIR)/inc -I$(RTE_SDK)/x86_64-native-linuxapp-gcc/include -I$(RAFT_DIR)/include -DNO_BATCH #-DACCELERATED #-DRAFT_STATS
+CFLAGS += -g -O3 -I$(ROOTDIR)/netstack/inc -I$(R2P2LIB_DIR)/inc -I$(RAFT_DIR)/include -DNO_BATCH #-DACCELERATED #-DRAFT_STATS
+
+DPDK_VERSION:=$(shell  pkg-config --modversion libdpdk)
+ifneq ("$(DPDK_VERSION)", "")
+       CFLAGS += ${shell pkg-config --cflags --static libdpdk}
+else
+       CFLAGS += -I$(RTE_SDK)/x86_64-native-linuxapp-gcc/include
+endif

 ifeq ($(WITH_RAFT), 1)
        CFLAGS += -DWITH_RAFT
@@ -72,7 +79,13 @@ WERROR_FLAGS += -Wformat-nonliteral -Wformat-security
 WERROR_FLAGS += -Wundef -Wwrite-strings

 CFLAGS += $(WERROR_FLAGS) -mavx2
-LDFLAGS= -Wl,--whole-archive -Wl,-ldpdk -Wl,--no-whole-archive -lrt -lpthread -lm -ldl -L$(RTE_SDK)/x86_64-native-linuxapp-gcc/lib -lconfig -lnuma -lgcov --coverage -lpcap
+
+ifneq ("$(DPDK_VERSION)", "")
+       LDFLAGS += ${shell pkg-config --libs --static libdpdk}
+else
+       LDFLAGS= -Wl,--whole-archive -Wl,-ldpdk -Wl,--no-whole-archive -lrt -lpthread -lm -ldl -L$(RTE_SDK)/x86_64-native-linuxapp-gcc/lib -lconfig -lnuma -lgcov --coverage -lpcap
+endif
+LDFLAGS += -lconfig -lgcov --coverage -lpcap

 SRCS_C := $(addprefix $(ROOTDIR)/netstack/dp/, $(DP_SRC)) $(addprefix $(ROOTDIR)/netstack/net/, $(NET_SRC)) $(addprefix $(R2P2LIB_DIR)/, $(R2P2_SRC_C))
 OBJS_C := $(patsubst %.c, %.o, $(SRCS_C))

this ensures we have fallback too

[vipinpv85]

makefile: support built with new version of dpdk

current makefile uses statically linked path for both CFLAGS and LDFLAGS.
Using `pkg-config` one can allow
 - custom path by updating PKG_CONFIG_PATH
 - supported from DPDK 19.11 LTS and higher

The fallback is to default (old) build CFLAGS and LDFLAGS.