include libpcap when checking for pcap symbol (#1313)

Signed-off-by: Glen Gibb <[email protected]>

Author: grg

src/BMI/CMakeLists.txt

@@ -1,8 +1,13 @@
 # Check for pcap_set_immediate_mode
-set(CMAKE_REQUIRED_LIBRARIES "pcap")
 include(CheckSymbolExists)
+
+set(_OLD_CMAKE_REQUIRED_LIBRARIES "${CMAKE_REQUIRED_LIBRARIES}")
+set(CMAKE_REQUIRED_LIBRARIES "pcap")
+
 check_symbol_exists(pcap_set_immediate_mode "pcap.h" HAVE_PCAP_SET_IMMEDIATE_MODE)
 
+set(CMAKE_REQUIRED_LIBRARIES "${_OLD_CMAKE_REQUIRED_LIBRARIES}")
+
 # Create bmi library
 add_library(bmi OBJECT
   bmi_interface.c