cmake: set include directories in case the target is used out of this project

When using pcap or pcap_static CMake target out of this project.
The compiler complains about missing "pcap.h" header.

This is because no proper include directories are setted with these targets.

Add a proper include_directories to both pcap and pcap_static targets.

Also bump the minimum cmake version to 2.8.11 to allow generator expressions.

Signed-off-by: Clément Péron <peron.clem@gmail.com>

Author: clementperon

CMakeLists.txt

@@ -3144,6 +3144,10 @@ if(BUILD_SHARED_LIBS)
         ${CMAKE_CURRENT_BINARY_DIR}/scanner.c
         ${PROJECT_EXTERNAL_OBJECT_LIST}
     )
+    target_include_directories(${LIBRARY_NAME} PUBLIC
+        $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
+        $<INSTALL_INTERFACE:include>
+    )
     add_dependencies(${LIBRARY_NAME} SerializeTarget)
     set_target_properties(${LIBRARY_NAME} PROPERTIES
         COMPILE_DEFINITIONS BUILDING_PCAP)
@@ -3169,6 +3173,10 @@ add_library(${LIBRARY_NAME}_static STATIC
     ${CMAKE_CURRENT_BINARY_DIR}/scanner.c
     ${PROJECT_EXTERNAL_OBJECT_LIST}
 )
+target_include_directories(${LIBRARY_NAME}_static PUBLIC
+    $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
+    $<INSTALL_INTERFACE:include>
+)
 add_dependencies(${LIBRARY_NAME}_static SerializeTarget)
 set_target_properties(${LIBRARY_NAME}_static PROPERTIES
     COMPILE_DEFINITIONS BUILDING_PCAP)