build: Add support for linking to shared falcosecurity libraries.

* cmake/modules/falcosecurity-libs.cmake (USE_BUNDLED_FALCOSECURITY_LIBS):
New option.  Look for libsinsp via pkg-config unless it's enabled.
* userspace/sysdig/CMakeLists.txt: Adjust link directives accordingly.
Remove extraneous zlib include.

Signed-off-by: Maxim Cournoyer <maxim.cournoyer@gmail.com>

cmake/modules/falcosecurity-libs.cmake

@@ -16,6 +16,19 @@
 # limitations under the License.
 #
 
+option(USE_BUNDLED_FALCOSECURITY_LIBS "Enable building of the bundled falcosecurity libraries" ${USE_BUNDLED_DEPS})
+
+if(NOT USE_BUNDLED_FALCOSECURITY_LIBS)
+    find_package(PkgConfig REQUIRED)
+    pkg_check_modules(LIBSINSP REQUIRED IMPORTED_TARGET libsinsp)
+    message(STATUS "Found libsinsp:
+  include: ${LIBSINSP_INCLUDE_DIRS}
+  lib: ${LIBSINSP_LIBRARIES}
+  cflags: ${LIBSINSP_CFLAGS}")
+    return()
+endif()
+
+# else(): using bundled falcosecurity libs
 set(FALCOSECURITY_LIBS_CMAKE_SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/cmake/modules/falcosecurity-libs-repo")
 set(FALCOSECURITY_LIBS_CMAKE_WORKING_DIR "${CMAKE_BINARY_DIR}/falcosecurity-libs-repo")
 

userspace/sysdig/CMakeLists.txt

@@ -20,7 +20,6 @@ if(NOT WIN32)
 	include(ncurses)
 endif() # NOT WIN32
 
-include(zlib)
 include(luajit)
 
 include_directories("${PROJECT_BINARY_DIR}/userspace/sinspui")
@@ -108,7 +107,7 @@ if(NOT WIN32)
 	include_directories(${PROJECT_BINARY_DIR}/driver/src)
 
 	target_link_libraries(sysdig
-		sinsp
+		$<IF:$<BOOL:${USE_BUNDLED_FALCOSECURITY_LIBS}>,sinsp,PkgConfig::LIBSINSP>
 		"${LUAJIT_LIB}"
 		"${YAMLCPP_LIB}")
 
@@ -117,7 +116,7 @@ if(NOT WIN32)
 	endif()
 
 	target_link_libraries(csysdig
-		sinsp
+		$<IF:$<BOOL:${USE_BUNDLED_FALCOSECURITY_LIBS}>,sinsp,PkgConfig::LIBSINSP>
 		"${LUAJIT_LIB}"
 		"${CURSES_LIBRARIES}"
 		"${YAMLCPP_LIB}")
@@ -140,12 +139,12 @@ else()
 	add_definitions(-DNOCURSESUI)
 
 	target_link_libraries(sysdig
-		sinsp
+		$<IF:$<BOOL:${USE_BUNDLED_FALCOSECURITY_LIBS}>,sinsp,PkgConfig::LIBSINSP>
 		"${LUAJIT_LIB}"
 		"${YAMLCPP_LIB}")
 
 	target_link_libraries(csysdig
-		sinsp
+		$<IF:$<BOOL:${USE_BUNDLED_FALCOSECURITY_LIBS}>,sinsp,PkgConfig::LIBSINSP>
 		"${LUAJIT_LIB}"
 		"${YAMLCPP_LIB}")