Address comment: disable WASM on s390x

CMakeLists.txt

@@ -400,6 +400,11 @@ if (FLB_SYSTEM_MACOS)
   include(cmake/macos-setup.cmake)
 endif()
 
+# Build for SystemZ - s390x arch
+if (FLB_SYSTEM_LINUX)
+  include(cmake/s390x.cmake)
+endif ()
+
 # Extract Git commit information for debug output.
 # Note that this is only set when cmake is run, the intent here is to use in CI for verification of releases so is acceptable.
 # For a better solution see https://jonathanhamberg.com/post/cmake-embedding-git-hash/ but this is simple and easy.

cmake/s390x.cmake

@@ -0,0 +1,6 @@
+if(CMAKE_SYSTEM_PROCESSOR MATCHES "^(SystemZ|s390x)")
+  message(STATUS "Forcing characters to be signed, as on x86_64.")
+  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fsigned-char")
+  message(STATUS "Cannot build WAMR on this platform, so WASM support is disabled.")
+  set(FLB_WASM OFF)
+endif ()