riscv64: add vector stpcpy().

Bug: https://github.com/google/android-riscv64/issues/107
Test: treehugger
Change-Id: Ic1fb9da974769d2767ea2c092a2e97e095612e6e
diff --git a/libc/arch-riscv64/static_function_dispatch.S b/libc/arch-riscv64/static_function_dispatch.S
index 3bf0275..f96d40e 100644
--- a/libc/arch-riscv64/static_function_dispatch.S
+++ b/libc/arch-riscv64/static_function_dispatch.S
@@ -40,6 +40,7 @@
 FUNCTION_DELEGATE(memcpy, memcpy_vext)
 FUNCTION_DELEGATE(memmove, memmove_vext)
 FUNCTION_DELEGATE(memset, memset_vext)
+FUNCTION_DELEGATE(stpcpy, stpcpy_vext)
 FUNCTION_DELEGATE(strcat, strcat_vext)
 FUNCTION_DELEGATE(strchr, strchr_vext)
 FUNCTION_DELEGATE(strcmp, strcmp_vext)