Add JINJA2CPP_PIC option which controls '-fPIC' option

Author: flexferrum

CMakeLists.txt

@@ -19,6 +19,7 @@ set (JINJA2CPP_DEPS_MODE "external" CACHE STRING "Jinja2Cpp dependency managemen
 option(JINJA2CPP_BUILD_TESTS "Build Jinja2Cpp unit tests" ${JINJA2CPP_IS_MAIN_PROJECT})
 option(JINJA2CPP_STRICT_WARNINGS "Enable additional warnings and treat them as errors" ON)
 option(JINJA2CPP_BUILD_SHARED "Build shared linkage version of Jinja2Cpp" OFF)
+option(JINJA2CPP_PIC "Control -fPIC option for library build" OFF)
 
 if (NOT JINJA2CPP_DEPS_MODE)
     set (JINJA2CPP_DEPS_MODE "internal")
@@ -69,8 +70,10 @@ if(NOT ${JINJA2CPP_WITH_SANITIZERS} STREQUAL "none")
 endif()
 
 if (UNIX)
-    set(GCC_CXX_FLAGS ${GCC_CXX_FLAGS} -fPIC)
-    set(CLANG_CXX_FLAGS ${CLANG_CXX_FLAGS} -fPIC)
+	if (JINJA2CPP_PIC OR CONAN_CMAKE_POSITION_INDEPENDENT_CODE)
+		set(GCC_CXX_FLAGS ${GCC_CXX_FLAGS} -fPIC)
+		set(CLANG_CXX_FLAGS ${CLANG_CXX_FLAGS} -fPIC)
+	endif ()
 else ()
     set(GCC_CXX_FLAGS ${GCC_CXX_FLAGS} "-Wa,-mbig-obj" -O1)
     if (${CMAKE_CXX_COMPILER_ID} MATCHES "GNU")