Don't use the private version of vasprintf(). It doesn't understand

Don't use the private version of vasprintf().  It doesn't understand
"%%" in format strings and tends to dump core for "%%st".  I needed
"%%st" to fix the new gdb ...

Don't use the private version of strerror() either.

Use INTERNALLIB and INTERNALSTATICLIB instead of a private install
rules NOPROFILE and NOPIC.  This is only slightly cleaner.
INTERNALLIB was previously only used in compatibility libraries
(libgnumalloc etc.) and INTERNALSTATICLIB was previously unused.
INTERNAL*LIB probably should be replaced by something like NOSTATICO
together with NO{STATICO,PROFILE,PIC}INSTALL.