Resolve conflicts for functions introduced in Android API level 21. * lib/string.in.h (stpcpy): Consider REPLACE_STPCPY. Disable _GL_CXXALIASWARN invocation on non-glibc systems. * m4/string_h.m4 (gl_STRING_H_DEFAULTS): Initialize REPLACE_STPCPY. * modules/string (Makefile.am): Substitute REPLACE_STPCPY. * m4/stpcpy.m4 (gl_FUNC_STPCPY): Conditionally set REPLACE_STPCPY. * modules/stpcpy (configure.ac): Consider REPLACE_STPCPY.