Revert: remove -fno-stack-protector from CFLAGS_TARGET

Was not the root cause of the __aeabi_read_tp linker error.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

env.sh

@@ -38,7 +38,7 @@ _env_register() {
 
     # Флаги тулчейна
     CFLAGS_TOOLSET='-O2'
-    CFLAGS_TARGET='-Os -mthumb -fno-stack-protector'
+    CFLAGS_TARGET='-Os -mthumb'
     CXXFLAGS_TARGET=$CFLAGS_TARGET
     LDFLAGS_TARGET='-Wl,--fdpic'