build: prevent the toolchain from emitting an executable stack

Signed-off-by: Eduardo Silva <eduardo@chronosphere.io>

Author: edsiper

CMakeLists.txt

@@ -83,6 +83,14 @@ if (MSVC)
   add_compile_options(/MT)
 else()
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall")
+  if (CMAKE_SYSTEM_NAME STREQUAL "Linux")
+    # Prevent the toolchain from emitting an executable stack on Linux targets,
+    # which triggers kernel warnings (e.g. "started with executable stack") and
+    # weakens security hardening. The linker flag is not supported on macOS.
+    add_compile_options(-Wa,--noexecstack)
+    set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -Wl,-z,noexecstack")
+    set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -Wl,-z,noexecstack")
+  endif()
   # The following flags are to enhance security, but it may impact performance,
   # we disable them by default.
   if (FLB_WASM_STACK_PROTECT)