riscv64: enable uClibc-ng ctors for noMMU config

target/riscv64/uclibc-ng-nommu.config

@@ -1,6 +1,6 @@
 #
 # Automatically generated file; DO NOT EDIT.
-# uClibc-ng 1.0.45 C Library Configuration
+# uClibc-ng 1.0.46 C Library Configuration
 #
 # TARGET_aarch64 is not set
 # TARGET_alpha is not set
@@ -70,6 +70,7 @@ DOPIC=y
 # STATIC_PIE is not set
 ARCH_HAS_NO_SHARED=y
 ARCH_HAS_NO_LDSO=y
+UCLIBC_CTOR_DTOR=y
 HAS_NO_THREADS=y
 PTHREADS_STACK_DEFAULT_SIZE=2097152
 UCLIBC_HAS_SYSLOG=y