Add stpcpy/stpncpy.

Add tests for the above.

Add the fortify implementations of __stpcpy_chk and __stpncpy_chk.

Modify the strncpy test to cover more cases and use this template for
stpncpy.

Add all of the fortify test cases.

Bug: 13746695
Change-Id: I8c0f0d4991a878b8e8734fff12c8b73b07fdd344
diff --git a/libc/Android.mk b/libc/Android.mk
index 44bf388..3eaff2f 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -96,6 +96,8 @@
     bionic/__memmove_chk.cpp \
     bionic/__read_chk.cpp \
     bionic/__recvfrom_chk.cpp \
+    bionic/__stpcpy_chk.cpp \
+    bionic/__stpncpy_chk.cpp \
     bionic/__strchr_chk.cpp \
     bionic/__strlcat_chk.cpp \
     bionic/__strlcpy_chk.cpp \
@@ -383,6 +385,8 @@
     upstream-openbsd/lib/libc/stdlib/strtoull.c \
     upstream-openbsd/lib/libc/stdlib/strtoumax.c \
     upstream-openbsd/lib/libc/stdlib/system.c \
+    upstream-openbsd/lib/libc/string/stpcpy.c \
+    upstream-openbsd/lib/libc/string/stpncpy.c \
     upstream-openbsd/lib/libc/string/strcasecmp.c \
     upstream-openbsd/lib/libc/string/strcspn.c \
     upstream-openbsd/lib/libc/string/strdup.c \